[tempay]

The SPDX license identifiers are the best thing we have for defining what the canonical version is (which is used by expat): https://spdx.org/licenses/MIT.html

There are many MIT-derrived licenses, some of which have identifiers prefixed with MIT- and others like X11 and curl have independent identifiers: https://spdx.org/licenses/

[F3nd0]

All the more reason to avoid calling any one licence ‘the MIT licence’, in my opinion. While I appreciate that SPDX provides a comprehensive list unambiguous identifiers, I don’t really see why they would be best suited to determine which of the many variants a name has been used for is the best candidate.

That’s not to say they necessarily aren’t; I’d be interested to see if any rationale behind that choice has been published anywhere. But if the choice was made more or less arbitrarily, or based on what seemed more popular to the authors, I’d be inclined not to treat SPDX as an authority on the matter.