[raimue]

A GPG public key does not only consist of the integer number that forms the cryptographic public key, but usually you have multiple user IDs so other can recognize to whom this key belongs. In order to prove that these user ID belongs to this public key, each of them is signed. Obviously, that will take a few more bytes for the additional data and signature.

The exported file size also depends on the way you export the GPG public key. By default, you will also export all signatures made by others, but you can use `gpg --export --export-options=export-minimal` to strip everything except the last self-signature on each user ID.