docs: Reference docs on generated flatbuffers in CONTRIBUTING.md
@@ -186,3 +186,20 @@ cargo clippy --all-targets --workspace -- -D warnings
[`rustfmt`]: https://github.com/rust-lang/rustfmt
[`clippy`]: https://github.com/rust-lang/rust-clippy
+
+## Upgrading the `flatbuffers` crate
+
+IOx uses Flatbuffers for its write-ahead log. The structure is defined in
+[`generated_types/protos/wal.fbs`]. We have then used the `flatc` Flatbuffers compiler to generate
+the corresponding Rust code in [`generated_types/src/wal_generated.rs`], which is checked in to the
+repository.
+
+The checked-in code is compatible with the `flatbuffers` crate version in the `Cargo.lock` file. If
+upgrading the version of the `flatbuffers` crate that IOx depends on, the generated code will need
+to be updated as well.
+
+Instructions for updating the generated code are in [`docs/regenerating_flatbuffers.md`].
+
+[`generated_types/protos/wal.fbs`]: generated_types/protos/wal.fbs
+[`generated_types/src/wal_generated.rs`]: generated_types/src/wal_generated.rs
+[`docs/regenerating_flatbuffers.md`]: docs/regenerating_flatbuffers.md
