vendor-bundle-conventions

# Vendored code A vendored bundle is a copy of somebody else's release, and the next upgrade is a straight overwrite. 1. Never reformat a vendored file: the diff against upstream is the only thing that shows what was changed on purpose. 2. Keep local changes in one patch file beside the bundle, never inline. 3. Record the upstream version in the bundle's own marker file, so an upgrade can tell what it is replacing.