License
Currently, LLVM releases are distributed under the Apache-2.0 with LLVM-exception license, an OSI-approved license.
However, LLVM releases prior to LLVM 8.0 was licensed under University of Illinois Open Source License
Discourse / Mailing list
If you are interested in LLVM you can follow along on our Discourse forum. New releases are posted to the Announce category which you can subscribe to in order to be notified via E-Mail.
GnuPG signing keys
The source packages and git tags are signed by the release managers. You can download the keys in order to verify here.
Download
LLVM provides extensive documentation in HTML form, which is available in the source download and online.