Is there really no manual for Bitcoin Core?
There is a manual documenting both examples. The man page for bitcoind.
man bitcoind shows me:
       -blocknotify=&lt;cmd&gt;

              Execute command when the best block changes (%s in cmd is replaced by block hash)
        ....
       -walletnotify=&lt;cmd&gt;

              Execute command when a wallet transaction changes (%s in cmd is replaced by TxID)

They're really not that hard to use.
Note that this machine runs a slightly older version of bitcoind. Newer versions support %w for the name of the wallet, as bitcoind now supports multiple wallets, in addition to %s for the transaction ID.