Why Do I Want To Hand Roll a BPF Token Delegation?

Anywhere I searched for “BPF tokens”, I kept getting something like, “BPF tokens let unprivileged containers load eBPF" and I wanted to use it, but all Google searches either led me to kernel commit messages or nearly 100% AI generated blog posts.

When I read these blog posts, they didn’t make sense, and I couldn’t find examples of failures someone ran into, or an explanation of why doing it a certain way led to failure, which IMO is critical to understanding the internals.

So I asked myself, can I build the entire token delegation handshake myself in one file and either create a token that I can pass to a process, or learn exactly why I can’t?