I would note that this seems to use British English as opposed to American English. Is there a general guideline as to which should be used (I.e., in American English, everything would consistently use "license").

And the term license isn't even used consistently in the documentation:

All contributions committed since July 1st, 2021, as well as some past contributions, are licensed under the MIT license. The MIT licence and more details are listed in the file LICENCE.MIT.

I.e., MIT license and MIT licence are both used in subsequent sentences.