Although IANA's summaries of application/pgp-encrypted, application/pgp-keys, and application/pgp-signature  all say that they are exclusively "7bit text", they also all reference RFC 3156 which says that these formats may be either text or binary:
"OpenPGP implementations can generate either ASCII armor or 8-bit binary output when encrypting data, generating a digital signature, or extracting public key data." 
Moreover, GPG's default is to create binary files rather than base64 ASCII files.
This reverts commit 2a82916e.
 https://www.iana.org/assignments/media-types/application/pgp-encrypted  https://www.iana.org/assignments/media-types/application/pgp-keys  https://www.iana.org/assignments/media-types/application/pgp-signature  https://www.rfc-editor.org/rfc/rfc3156