A "brief explanation" means giving a short and simple description or answer to something, without going into a lot of detail or elaboration. Full definition
This is different from a traditional resume that displays a timeline of reverse chronological work experience with brief explanations of each job. (thebalance.com)
Closing Costs A list of fees that you'll have to make during the closing with brief explanations. (mortgage-x.com)
Also included are brief explanations as to why these tricks work, and some meal suggestions. (wizzley.com)