A manifest file is required to be included with any packaged extension, declaring metadata about the extension itself, it's resources, and the permissions required for it to function among other things. Manifests contain specifics about the manifest version and browser the extension is built for.
Manifest files are intended to be generated and placed in a generated code folder along with any other pre-built files, prior to the extension being built using webpack. We expect during the later building of the extension that any generated files will be copied to their final destination.
The run.ts script is run using bun:
# Generate manifest file Chromium browsers
bun meta/manifest/run.ts --browser chromium