Enter a clue or pattern or both:
The Clue
Certain e-mail attachment (3 letter answer)
The Answer
PDF
Tags
Notes
The answer PDF is rarely seen, appearing only about once every 1800 puzzles.
Related Clues
.doc alternative
Sharable PC file
Alternative to a print version: Abbr.
Sharable computer file, for short
Suffix for many a computer attachment
Suffix for many a sharable computer file