e.g. https://github.com/kulfi-project/kulfi/blob/malai-0.2.5/kulf...
$ echo -n c1b2d4463e503765b7422e126ea7ff5633ba5903f97b700ac818 | wc -c
52
I figured as much, but that's an example for an id52, but not a description of what it is.
The actual answer seems to be that these are zbase32-encoded 32 byte iroh node IDs: https://www.iroh.computer/blog/iroh-global-node-discovery