For those reading: after you select a collection, there is a small "i" icon at the top of the screen, near the search bar. Clicking it gives a link to the source and license info!
----
Though as others have mentioned: beware that there is still obviously-trademarked stuff in there, and ones that may require attribution; check the source to be sure. If you're looking at a specific icon, there doesn't seem to be an obvious way to get back to the collection it came from (and thus see the original license terms).
For those reading: after you select a collection, there is a small "i" icon at the top of the screen, near the search bar. Clicking it gives a link to the source and license info!
----
Though as others have mentioned: beware that there is still obviously-trademarked stuff in there, and ones that may require attribution; check the source to be sure. If you're looking at a specific icon, there doesn't seem to be an obvious way to get back to the collection it came from (and thus see the original license terms).