The most common and most likely answer to this crossword clue is the 8 letter word TIMELINE
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More clues leading to the result TIMELINE
Buddy explains!

The straight part
We know that "FB feature" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case fb feature = timeline.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 TIMELINE mean?
TIMELINE noun- A graphical representation of a chronological sequence of events (past or future); a chronology.
- A schedule of activities; a timetable.
- An individual universe or reality, especially a parallel/alternate one in which events differ from actual history, or differ from the established canon of a fictional world.
- To analyse a sequence of events or activities.
- To display such a sequence graphically.
- A metaphorical conception of time as a stream, or flowing body of water.