We're talking about the company that had to contribute arbitrary-length command lines to the Linux kernel, and whose flags library supports reading the flags from a file, in case your appetite for flags is insatiable.
Lots of flag libraries support @argfiles, it's useful for Windows amongst other places.
The real fun story about Google and flags is from the days when their flags library supported flags being passed in gzipped base64 form ... via a flag. I think the reason was there was a server that could take the whole configuration in the form of a flag, but it had got too large for Linux at some point and they didn't want to load the config from a file because there was better support for canaried/partial rollouts of flag changes than data file changes. Or something like that.
The real fun story about Google and flags is from the days when their flags library supported flags being passed in gzipped base64 form ... via a flag. I think the reason was there was a server that could take the whole configuration in the form of a flag, but it had got too large for Linux at some point and they didn't want to load the config from a file because there was better support for canaried/partial rollouts of flag changes than data file changes. Or something like that.