Do you know Naver also has keyword insertion function?

Yes, they do have!
but it's not the format we use in Google , {KEYWORD:ABC} but this is the one <키워드:ABC>.

키워드 = keyword

Once you use this, in the result page the keyword will be displayed in bold.

I marked in red for the bold characters in the ad copy.
It means the advertiser is using the Dynamic keyword insertion function.