Though I will say having Ubuntu in the licensing name probably won't stop people from using the license if its a good fit for their needs. Historically that really hasn't worked that way. Didn't stop people from picking up the MIT X11 license and reusing it outside of its original use by MIT. Hasn't stopped people using the BSD license outside of BSD. Hasn't stopped the uptake of the Affero GPL license even though Affero Inc. is a privately held for-profit entity. If this "interim" license hangs around too long.. its not going to be "interim" for other people who pick it up and reuse it...or fork this font into a new project. The forked project won't have to follow Canonical's planned re-licensing. I could take the published font right now...fork it..rename it..and we'd be stuck with the "interim" license terms on something.
What's more disturbing still is the blanket copyright assignment requirement to Canonical for these fonts. Canonical continues to push its copyright assignment agenda. Aaron Siego's comments about how Canonical's assignment policy could be fixed to be more balanced and still provide good-faith re-licensing powers is an important read.
Read the comment discussion. You can have a contributor agreement that gives a central authority _limited_ ability to relicense in good-faith without giving them the power to create a proprietary fork of the codebase. Aaron goes to some length explaining how KDE's managing entity does this to balance all interests.
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