diff --git a/engine/src/flutter/lib/snapshot/BUILD.gn b/engine/src/flutter/lib/snapshot/BUILD.gn
index 618640efe53..bf08b11d865 100644
--- a/engine/src/flutter/lib/snapshot/BUILD.gn
+++ b/engine/src/flutter/lib/snapshot/BUILD.gn
@@ -26,6 +26,19 @@ group("generate_snapshot_bins") {
   }
 }
 
+# Uses gen_snapshot to compile a Dart core platform snapshot.
+#
+# Inputs:
+#   * platform_strong.dill
+#
+# Outputs:
+#   * vm_snapshot_data.bin
+#   * vm_snapshot_instructions.bin
+#   * isolate_snapshot_data.bin
+#   * isolate_snapshot_instructions.bin
+#
+# See: `bin_to_linkable` rules below that build these outputs into linkable form
+# See: https://github.com/flutter/flutter/wiki/Flutter-engine-operation-in-AOT-Mode
 compiled_action("generate_snapshot_bin") {
   if (target_cpu == "x86" && host_os == "linux") {
     # By default Dart will create a 32-bit gen_snapshot host binary if the target
@@ -157,6 +170,9 @@ template("bin_to_coff") {
   }
 }
 
+# Generates a linkable output file defining the specified symbol with the bytes
+# from the binary file. Emits a COFF object file when targeting Windows,
+# otherwise assembly.
 template("bin_to_linkable") {
   assert(defined(invoker.deps), "Must define deps")
   assert(defined(invoker.input), "Must define input binary file")
@@ -207,6 +223,11 @@ bin_to_linkable("platform_strong_dill_linkable") {
   executable = false
 }
 
+# Creates a `gen_snapshot` binary suffixed with the target platform.
+#
+# Builds gen_snapshot using the host toolchain then copies the resulting binary
+# to `gen_snapshot_armv7` or `gen_snapshot_arm64` depending on the target
+# platform.
 if (host_os == "mac" && (target_cpu == "arm" || target_cpu == "arm64")) {
   action("create_arm_gen_snapshot") {
     host_output_dir = get_label_info(
@@ -261,6 +282,7 @@ source_set("snapshot") {
             get_target_outputs(":platform_strong_dill_linkable")
 }
 
+# Compiles the Dart/Flutter core libraries to kernel bytecode.
 compile_platform("strong_platform") {
   single_root_scheme = "org-dartlang-sdk"
   single_root_base = rebase_path("../../../")