The most common and most likely answer to this crossword clue is the 4 plus 6 letter word TIME STAMPS
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Buddy explains!

The straight part
We know that "Records/when things happened" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case records/when things happened = time stamps.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 TIME STAMPS mean?
TIME STAMPS noun- A variable containing the date and time at which an event occurred, often included in a log to track the sequence of events.
- To record the date and time of (an event, etc).