What is a clearsigned message? PGP Digital Timestamping Service webpage mentions

The service operates in a number of different &quot;modes&quot; depending upon the required results. The current modes are:-
post: forwarding an outbound message with a proof of posting certificate
clear: the received message is clearsigned and returned to the sender
header: the received message (with headers) is clearsigned and returned to the sender
text: the received message is signed and returned ASCII armoured to the sender
pgp: the received message (which must be ASCII armoured) is assumed to be a PGP file which is then signed and returned to the sender
binary: the received message (which must be ASCII armoured) is assumed not to be a PGP file which is then signed and returned to the sender


What is a clearsigned message? I searched around quite a bit using Duck Duck Go, and on this site but I couldn't find an explanation.
From dictionary.university with search clearsigned definition


Dictionary of Internet Terms A digitally signed S/MIME or PGP message in which the content of the message is readable even if the signature is not.




A message that is digitally signed but not encrypted.


These might be helpful, too;

Cleartext  is readable data transmitted or stored “in the clear” (i.e. unencrypted)

Plaintext is the input to an encryption algorithm

Ciphertext is the unreadable output of an encryption algorithm

Plain text means its text that hasn’t been formatted (i.e., a plain text file)
Note that plain text might be an ambiguous term without context. See the commnets.