clarkwinkelmann Hi,
I have the same issue than @DearTanker about wikimedia/less.php.
I had a line in composer.json that I removed but I still have the same return of the "why-not" function :
composer why-not flarum/core v0.1.0-beta.13
flarum/core v0.1.0-beta.13 requires wikimedia/less.php (^3.0)
flarum/flarum - does not require wikimedia/less.php (but v2.0.0 is installed)