This also increases compliance by adding `default_applicable_licenses` to several `BUILD` files that previously did not have it.
PiperOrigin-RevId: 670784686
This CL is mostly a no-op, except that now google3-only code is actually stripped from OSS, instead of being preserved in `# begin:google_only` blocks.
This follows the conventions of the greater Copybara ecosystem.
PiperOrigin-RevId: 669513564
This simplifies upb by removing differences between google3 and OSS.
This also points upb at the protobuf license, instead of keeping a separate copy around for upb.
PiperOrigin-RevId: 669447145