diff --git a/benches/lib.rs b/benches/lib.rs
index 395f10f..1131f34 100644
--- a/benches/lib.rs
+++ b/benches/lib.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 use std::hint::black_box;
 use std::mem;
 
diff --git a/build.rs b/build.rs
index e5ef535..2e52f02 100644
--- a/build.rs
+++ b/build.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 fn main() {
     #[cfg(windows)]
     if std::env::var("CARGO_CFG_TARGET_OS").unwrap_or_default() == "windows" {
diff --git a/src/apperr.rs b/src/apperr.rs
index bb6ee4d..b1dd6d2 100644
--- a/src/apperr.rs
+++ b/src/apperr.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 //! Provides a transparent error type for edit.
 
 use std::{io, result};
diff --git a/src/arena/debug.rs b/src/arena/debug.rs
index 34209ae..4b1ae6c 100644
--- a/src/arena/debug.rs
+++ b/src/arena/debug.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 #![allow(clippy::missing_safety_doc, clippy::mut_from_ref)]
 
 use std::alloc::{AllocError, Allocator, Layout};
diff --git a/src/arena/mod.rs b/src/arena/mod.rs
index ac43fb9..a7099c7 100644
--- a/src/arena/mod.rs
+++ b/src/arena/mod.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 //! Arena allocators. Small and fast.
 
 #[cfg(debug_assertions)]
diff --git a/src/arena/release.rs b/src/arena/release.rs
index 8edcc8d..dec572c 100644
--- a/src/arena/release.rs
+++ b/src/arena/release.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 #![allow(clippy::mut_from_ref)]
 
 use std::alloc::{AllocError, Allocator, Layout};
diff --git a/src/arena/scratch.rs b/src/arena/scratch.rs
index c359a05..a719db4 100644
--- a/src/arena/scratch.rs
+++ b/src/arena/scratch.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 use std::ops::Deref;
 
 #[cfg(debug_assertions)]
diff --git a/src/arena/string.rs b/src/arena/string.rs
index c7e2ebc..ff70ec1 100644
--- a/src/arena/string.rs
+++ b/src/arena/string.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 use std::fmt;
 use std::ops::{Bound, Deref, DerefMut, RangeBounds};
 
diff --git a/src/base64.rs b/src/base64.rs
index e1f4de1..bce13c6 100644
--- a/src/base64.rs
+++ b/src/base64.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 //! Base64 facilities.
 
 use crate::arena::ArenaString;
diff --git a/src/bin/edit/documents.rs b/src/bin/edit/documents.rs
index 1ca5693..349f4f3 100644
--- a/src/bin/edit/documents.rs
+++ b/src/bin/edit/documents.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 use std::collections::LinkedList;
 use std::ffi::OsStr;
 use std::fs::File;
diff --git a/src/bin/edit/draw_editor.rs b/src/bin/edit/draw_editor.rs
index ecf8fd4..bdab25a 100644
--- a/src/bin/edit/draw_editor.rs
+++ b/src/bin/edit/draw_editor.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 use edit::framebuffer::IndexedColor;
 use edit::helpers::*;
 use edit::icu;
diff --git a/src/bin/edit/draw_filepicker.rs b/src/bin/edit/draw_filepicker.rs
index 6e51450..5bb30b4 100644
--- a/src/bin/edit/draw_filepicker.rs
+++ b/src/bin/edit/draw_filepicker.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 use std::cmp::Ordering;
 use std::fs;
 use std::path::PathBuf;
diff --git a/src/bin/edit/draw_menubar.rs b/src/bin/edit/draw_menubar.rs
index 3266b3c..95176c3 100644
--- a/src/bin/edit/draw_menubar.rs
+++ b/src/bin/edit/draw_menubar.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 use edit::arena_format;
 use edit::helpers::*;
 use edit::input::{kbmod, vk};
diff --git a/src/bin/edit/draw_statusbar.rs b/src/bin/edit/draw_statusbar.rs
index 4b1dcb7..ecbc5e4 100644
--- a/src/bin/edit/draw_statusbar.rs
+++ b/src/bin/edit/draw_statusbar.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 use edit::framebuffer::{Attributes, IndexedColor};
 use edit::helpers::*;
 use edit::input::vk;
diff --git a/src/bin/edit/localization.rs b/src/bin/edit/localization.rs
index 55a7d11..115f888 100644
--- a/src/bin/edit/localization.rs
+++ b/src/bin/edit/localization.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 use edit::arena::scratch_arena;
 use edit::sys;
 
diff --git a/src/bin/edit/main.rs b/src/bin/edit/main.rs
index f2cfc26..f4442a2 100644
--- a/src/bin/edit/main.rs
+++ b/src/bin/edit/main.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 #![feature(let_chains, linked_list_cursors, os_string_truncate, string_from_utf8_lossy_owned)]
 
 mod documents;
diff --git a/src/bin/edit/state.rs b/src/bin/edit/state.rs
index 88df404..df0d3b3 100644
--- a/src/bin/edit/state.rs
+++ b/src/bin/edit/state.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 use std::borrow::Cow;
 use std::ffi::{OsStr, OsString};
 use std::mem;
diff --git a/src/buffer/gap_buffer.rs b/src/buffer/gap_buffer.rs
index 12942c7..c78e84b 100644
--- a/src/buffer/gap_buffer.rs
+++ b/src/buffer/gap_buffer.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 use std::ops::Range;
 use std::ptr::{self, NonNull};
 use std::slice;
diff --git a/src/buffer/mod.rs b/src/buffer/mod.rs
index 2972b1a..8521285 100644
--- a/src/buffer/mod.rs
+++ b/src/buffer/mod.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 //! A text buffer for a text editor.
 //!
 //! Implements a Unicode-aware, layout-aware text buffer for terminals.
diff --git a/src/buffer/navigation.rs b/src/buffer/navigation.rs
index cac5ed2..a3c6aa8 100644
--- a/src/buffer/navigation.rs
+++ b/src/buffer/navigation.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 use std::ops::Range;
 
 use crate::document::ReadableDocument;
diff --git a/src/cell.rs b/src/cell.rs
index 64f9e3f..0e29039 100644
--- a/src/cell.rs
+++ b/src/cell.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 //! [`std::cell::RefCell`], but without runtime checks in release builds.
 
 #[cfg(debug_assertions)]
diff --git a/src/document.rs b/src/document.rs
index 64b6fec..0ae9eb8 100644
--- a/src/document.rs
+++ b/src/document.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 //! Abstractions over reading/writing arbitrary text containers.
 
 use std::ffi::OsString;
diff --git a/src/framebuffer.rs b/src/framebuffer.rs
index a33353e..6c96e9f 100644
--- a/src/framebuffer.rs
+++ b/src/framebuffer.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 //! A shoddy framebuffer for terminal applications.
 
 use std::cell::Cell;
diff --git a/src/fuzzy.rs b/src/fuzzy.rs
index 48f38ba..a449d7a 100644
--- a/src/fuzzy.rs
+++ b/src/fuzzy.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 //! Fuzzy search algorithm based on the one used in VS Code (`/src/vs/base/common/fuzzyScorer.ts`).
 //! Other algorithms exist, such as Sublime Text's, or the one used in `fzf`,
 //! but I figured that this one is what lots of people may be familiar with.
diff --git a/src/hash.rs b/src/hash.rs
index 914d48d..0634529 100644
--- a/src/hash.rs
+++ b/src/hash.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 //! Provides fast, non-cryptographic hash functions.
 
 /// The venerable wyhash hash function.
diff --git a/src/helpers.rs b/src/helpers.rs
index c1f6b1b..569218d 100644
--- a/src/helpers.rs
+++ b/src/helpers.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 //! Random assortment of helpers I didn't know where to put.
 
 use std::alloc::Allocator;
diff --git a/src/icu.rs b/src/icu.rs
index 45c8433..0829970 100644
--- a/src/icu.rs
+++ b/src/icu.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 //! Bindings to the ICU library.
 
 use std::cmp::Ordering;
diff --git a/src/input.rs b/src/input.rs
index 204eb2e..88a32ac 100644
--- a/src/input.rs
+++ b/src/input.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 //! Parses VT sequences into input events.
 //!
 //! In the future this allows us to take apart the application and
diff --git a/src/lib.rs b/src/lib.rs
index 503c3e7..ed0b978 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 #![feature(
     allocator_api,
     breakpoint,
diff --git a/src/oklab.rs b/src/oklab.rs
index 9759cce..5af68bf 100644
--- a/src/oklab.rs
+++ b/src/oklab.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 //! Oklab colorspace conversions.
 //!
 //! Implements Oklab as defined at: <https://bottosson.github.io/posts/oklab/>
diff --git a/src/path.rs b/src/path.rs
index 1b49b2e..45ba6ac 100644
--- a/src/path.rs
+++ b/src/path.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 //! Path related helpers.
 
 use std::ffi::OsStr;
diff --git a/src/simd/memchr2.rs b/src/simd/memchr2.rs
index 9b8ff10..be2980e 100644
--- a/src/simd/memchr2.rs
+++ b/src/simd/memchr2.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 //! `memchr`, but with two needles.
 
 use std::ptr;
diff --git a/src/simd/memrchr2.rs b/src/simd/memrchr2.rs
index c5b7bf8..26a5a55 100644
--- a/src/simd/memrchr2.rs
+++ b/src/simd/memrchr2.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 //! `memchr`, but with two needles.
 
 use std::ptr;
diff --git a/src/simd/memset.rs b/src/simd/memset.rs
index 7748440..028b66b 100644
--- a/src/simd/memset.rs
+++ b/src/simd/memset.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 //! `memchr` for arbitrary sizes (1/2/4/8 bytes).
 //!
 //! Clang calls the C `memset` function only for byte-sized types (or 0 fills).
diff --git a/src/simd/mod.rs b/src/simd/mod.rs
index a114135..79414d8 100644
--- a/src/simd/mod.rs
+++ b/src/simd/mod.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 //! Provides various high-throughput utilities.
 
 mod memchr2;
diff --git a/src/sys/mod.rs b/src/sys/mod.rs
index df204a8..f5305c0 100644
--- a/src/sys/mod.rs
+++ b/src/sys/mod.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 //! Platform abstractions.
 
 use std::fs::File;
diff --git a/src/sys/unix.rs b/src/sys/unix.rs
index 5ef9b50..b32d9a9 100644
--- a/src/sys/unix.rs
+++ b/src/sys/unix.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 //! Unix-specific platform code.
 //!
 //! Read the `windows` module for reference.
diff --git a/src/sys/windows.rs b/src/sys/windows.rs
index 4a1bae5..952ca47 100644
--- a/src/sys/windows.rs
+++ b/src/sys/windows.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 use std::ffi::{CStr, OsString, c_void};
 use std::fmt::Write as _;
 use std::fs::{self, File};
diff --git a/src/tui.rs b/src/tui.rs
index 6407ec6..fc7db5f 100644
--- a/src/tui.rs
+++ b/src/tui.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 //! An immediate mode UI framework for terminals.
 //!
 //! # Why immediate mode?
diff --git a/src/unicode/measurement.rs b/src/unicode/measurement.rs
index eb1540d..7f64538 100644
--- a/src/unicode/measurement.rs
+++ b/src/unicode/measurement.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 use std::hint::cold_path;
 
 use super::Utf8Chars;
diff --git a/src/unicode/mod.rs b/src/unicode/mod.rs
index ee139ee..20cf301 100644
--- a/src/unicode/mod.rs
+++ b/src/unicode/mod.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 //! Everything related to Unicode lives here.
 
 mod measurement;
diff --git a/src/unicode/tables.rs b/src/unicode/tables.rs
index c90882e..dc2ffa4 100644
--- a/src/unicode/tables.rs
+++ b/src/unicode/tables.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 // BEGIN: Generated by grapheme-table-gen on 2025-03-31T16:50:08Z, from Unicode 16.0.0, with --lang=rust --extended --no-ambiguous --line-breaks, 16950 bytes
 #[rustfmt::skip]
 const STAGE0: [u16; 544] = [
diff --git a/src/unicode/utf8.rs b/src/unicode/utf8.rs
index 7fcefc7..7ad05dd 100644
--- a/src/unicode/utf8.rs
+++ b/src/unicode/utf8.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 use std::{hint, iter};
 
 /// An iterator over UTF-8 encoded characters.
diff --git a/src/vt.rs b/src/vt.rs
index 2306ce5..31701c0 100644
--- a/src/vt.rs
+++ b/src/vt.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 //! Our VT parser.
 
 use std::{mem, time};
diff --git a/tools/grapheme-table-gen/src/main.rs b/tools/grapheme-table-gen/src/main.rs
index c0e0410..6e05d5a 100644
--- a/tools/grapheme-table-gen/src/main.rs
+++ b/tools/grapheme-table-gen/src/main.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 mod rules;
 
 use crate::rules::{JOIN_RULES_GRAPHEME_CLUSTER, JOIN_RULES_LINE_BREAK};
diff --git a/tools/grapheme-table-gen/src/rules.rs b/tools/grapheme-table-gen/src/rules.rs
index 9fe7874..7ddadb3 100644
--- a/tools/grapheme-table-gen/src/rules.rs
+++ b/tools/grapheme-table-gen/src/rules.rs
@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
 // Used as an indicator in our rules for ÷ ("does not join").
 // Underscore is one of the few characters that are permitted as an identifier,
 // are monospace in most fonts and also visually distinct from the digits.