We use the SPDX license identifiers (from the SPDX License List) in some places to identify the covered license.
These are included in Licenses/ verbatim, here are the original sources:
For the avoidance of doubt, the intention is that anyone can use the CC-BY-4.0 licensed avatar mesh and associated dev kit to create assets such as skins, clothing, attachments, etc. which they may distribute for free or for a charge. They can also bundle in the free mesh avatar, HUD and associated CC-BY-4.0 assets for convenience where useful.