Ah, you're delving into the world of file verification! SHA256SUMS.asc is a PGP-signed file that contains SHA-256 cryptographic hashes.

When you download a software, alongside it, there's often this SHA256SUMS.asc file. It contains the hash values of the original files. You can use these to verify your download hasn't been tampered with.

The ".asc" part means it's been signed with a PGP key - usually by the developer or organization that created the software. You can check this signature to make sure even the checksums haven't been messed around with!

Pretty nifty for security and integrity checks, right?