as_license_is_free_license() classifies strings like "MIT License" as non-free

[weimzh]

This is used by some of the third-party packages, like the official RPM package of microsoft's powershell, which is MIT licensed.

It might be better to ignore the token "License" itself rather than considering the word "License" itself as non-free.

[ximion]

This is not a bug, as long as "MIT License" is the string you are trying to check. The parameter to this function must be a SPDX license ID or expression, so only "MIT" would be considered valid.
See https://www.freedesktop.org/software/appstream/docs/chap-Metadata.html#tag-project_license for the specification entry and https://spdx.org/licenses/ for a list of valid license IDs.

[ximion]

Quick tip: If you have AppStream >= 0.14.6, you can use the check-license subcommand of appstreamcli to find out what AppStream thinks about a license:
appstreamcli check-license MIT will give you the right result, appstreamcli check-license 'MIT License' will tell you that the license is invalid/unknown.