Meaning:
“复” means “to review, analyze,” and “盘” means “a game set.” Originally a term used in the game of go, the term refers to the practice of two player repeating their moves in a game of go and examining each move in order to gain a better insight of the game. The term “to analyze post-game” is used in a more general sense nowadays, when a person tries to reexamine what they have done and find out ways to improve.
Example:
A: 昨天我请假了，听说老板召集大家开会，讲了什么？
Zuótiān wǒ qǐngjià le，tīngshuō lǎobǎn zhàojí dàjiā kāihuì，jiǎng le shénme？
I took a day off yesterday. I heard that the boss convened a meeting. What was it about?
B: 我们复盘了刚刚结束的年中促销，希望下次活动做得更好。
Wǒmen fùpán le gānggāng jiéshù de niánzhōng cùxiāo，xīwàng xiàcì huódòng zuòde gènghǎo。
We did a post-game analysis of the midyear sales campaign, in the hope that we will do better next time.