Presumably a script that aliases a common thing or something and then it uses the same. E.g. someone adds ./sed that has some default params and calls sed. You’re intended to call it with ~/not-in-path/defaulted/sed and it is supposed to then call sed but instead calls itself if it’s earlier in the path hierarchy.

Might even be as simple as “detect if I’m running gnu sed or bsd sed and use the appropriate one”. Obviously you can not have this problem by being smart about other things but defense in depth right?