Where are license keys stored? What's a .pubkey file?
Each premium extra will store a license key in the core/components/name-of-extra/ directory, in a file called .pubkey.
If you're using a workflow based on a version control system like git, you should exclude these files. If you don't, you might run into license issues during/after deployments, despite the proper licenses being available.
You normally don't have to update any of these files manually. Our license checks manage their contents for you, and automatically update it when a new license has been attached to a domain. It is also safe to remove them (e.g. if a package installation refuses to work because of a license issue) as they will be automatically restored.