The most common and most likely answer to this crossword clue is the 7 letter word DOSSIER
I've seen this crossword clue in The Guardian
D
O
S
S
I
E
R
More clues leading to the result DOSSIER
- Vagrant crossing island for papers
- Tramp clutching paper documents
- Report vagrant hanging around island
- Achiever filing two strong leaders and one report
- One opening homeless person’s file
- He sleeps rough, clutching current papers
- Record of tramp embracing setter
- In the Stasi, the DDR citizen is in the file
- Vagrant clutches one set of papers
- Tramp welcomes compiler portfolio
Buddy explains!

The straight part
We know that "brief" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case brief = dossier.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 DOSSIER mean?
DOSSIER noun- A collection of papers and/or other sources, containing detailed information about a particular person or subject, together with a synopsis of their content.