Flarum\Frontend\Compiler  

AssetsRevision

Produces a single token representing the current state of all compiled asset revisions, so a long-lived client can detect when the assets it booted with have been superseded (e.g. after a rebuild or extension toggle).

DatabaseVersioner

Records asset revisions one row at a time, so several instances can record different assets at once.

FileVersioner

JsCompiler

JsDirectoryCompiler

Used to copy JS files from a package directory to the assets' directory.

LessCompiler

RevisionCompiler

CompilerInterface

VersionerInterface

Records which revision of each compiled asset is current, so that a URL can be cache-busted and a client can tell when what it loaded was superseded.