ASCII text file vs text file

ASCII text file and text file both are nouns.

Word	Noun	Adjective	Verb	Adverb
ASCII text file	Yes	No	No	No
text file	Yes	No	No	No

As nouns, text file is a hypernym of ASCII text file; that is, text file is a word with a broader meaning than ASCII text file:

ASCII text file: a text file that contains only ASCII characters without special formatting
text file: (computer science) a computer file that contains text (and possibly formatting instructions) using seven-bit ASCII characters

Other hypernyms of ASCII text file include document.

ASCII text file (noun)	text file (noun)
a text file that contains only ASCII characters without special formatting	(computer science) a computer file that contains text (and possibly formatting instructions) using seven-bit ASCII characters