Human-readable dump of gpg public key

Try

gpg --list-packets --verbose < pubkey.asc

It doesn't dump the key data, but it shows all the other details. To dump additional raw data parts you need debug flag 2, so add --debug 0x02, this will dump the keys and other data in hex. This works in GPG versions 1.2 and 1.4, but sadly not in 2.0 as support for dumping bignum (MPI) data is not enabled (see DBG_MPI in g10/parse-packet.c) for some reason.

Also try pgpdump:

pgpdump < pubkey.asc

While waiting for answers, I read RFC4880 (OpenPGP) and came up with some code of my own to parse and print the relevant portion of an exported packet stream. Far from complete, but it might be useful to others, so I'm posting this as well. Right now I see little benefit over that pgpdump suggested by @grawity, but who knows…

I've used pgpdump It works well, and shows nice human-readable output. It doesn't yet print Elliptic Curve keys, but it will at least tell you it is an EC key. If you select the "dump literals" option, it will show you the actual key data.