The most common and most likely answer to this crossword clue is the 8 letter word SHEBANGS
I've seen this crossword clue in The Guardian
S
H
E
B
A
N
G
S
More clues leading to the result SHEBANGS
Buddy explains!

The straight part
We know that "matters" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case matters = shebangs.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SHEBANGS mean?
SHEBANGS noun- The character string "#!" used at the beginning of a computer file to indicate which interpreter can process the commands in the file, chiefly used in Unix and related operating systems.