This is not a good example - JWT is the name of a format, not of the token stored in that format. JWT token just means "token in JWT format".

Saying "a JWT" is in fact more dubious, like saying "an SQL" instead of "an SQL string".

https://datatracker.ietf.org/doc/html/rfc7519 disagrees:

Abstract

JSON Web Token (JWT) is a compact, URL-safe means of representing claims to be transferred between two parties. The claims in a JWT are encoded as a JSON object that is used as the payload of a JSON Web Signature (JWS) structure or as the plaintext of a JSON Web Encryption (JWE) structure, enabling the claims to be digitally signed or integrity protected with a Message Authentication Code (MAC) and/or encrypted.

Even the quoted fragment is a bit debatable - while the standard does commonly use "JWT" to mean a particular token, the very first sentence is only grammatical if we take JWT to be the name of the standard/format. Otherwise, it's missing an article - it should have been "*A* JSON Web Token (JWT) is [...]" if it were consistently used to refer to individual tokens, not the collective format.

> like saying "an SQL"

An SQL is an implementation of the System Query Language isn’t it? Like MySQL, or MSSQL.