I very much like the idea of a uniform algorithm for this - similarly to https://indieweb.org/post-type-discovery. During that session the list on https://spdx.org/licenses/ came up as a source for licence indication - unfortunately neither rel=“licence” nor microformats seem to be offering a way to indicate a machine readable licence indicator yet. It might be beneficial to include a proposition for that along with the algorithm.
If this entry helped you, or you simply liked it, leave a tip via
Monzo (only in the UK or via Google Pay) or Paypal