Anthropic's developer documentation: https://platform.claude.com/llms.txt. There's also https://platform.claude.com/llms-full.txt which is (WARNING) much bigger. Not sure where this second one fits into the standard.

Mintlify generates an llms.txt and llms-full.txt for all documentation sites. These work really well:

- https://cloud.laravel.com/docs/llms.txt

- https://cloud.laravel.com/docs/llms-full.txt