Emit a warning if PACKAGE has an invalid 'source' field, or if that 'source' is not reachable.

Check if there are flags set (for example, in #:configure-flags) which can be set as part of the build system.

Check for collisions that would occur when installing PACKAGE as a result of the propagated inputs it pulls in.

Emit a warning if the patches requires by PACKAGE are badly named or if the patch could not be found.

Check whether PACKAGE's name matches our guidelines.

Emit a warning if PACKAGE's origin has no meaningful file name.

Check whether PACKAGE explicitly requests to run tests, which is superfluous when building natively and incorrect when cross-compiling.

Check whether PACKAGE's source code is archived on Software Heritage. If it's not, and if its source code is a VCS snapshot, then send a "save" request to Software Heritage.

Software Heritage imposes limits on the request rate per client IP address. This checker prints a notice and stops doing anything once that limit has been reached.

Emit a warning if PACKAGE has an invalid 'home-page' field, or if that 'home-page' is not reachable.

Emit a warning if PACKAGE's source is an autogenerated tarball.

Emit a warning for labels that differ from the corresponding package name.