Basically, if we can't find out *for sure* that this is intended, we shouldn't change it, unless someone more familiar with this area of the codebase green lights it.

You'd basically start by `git blame`-ing this file (or use the Github UI for that) and figure out who added the comment about "they must be strings", see if it's related to an old issue, pull up the discussion, etc.

And also look at changes to this file since then and look for commits that explicitly say "allow attributes to also return symbolized keys", or something similar.