Is there also a badge for members who have reported valid security bugs here in past? Is record of such data kept here ?
Yeah, there is one profile I have seen from about 10 years ago with the badge, forgot the username.
There is also a badge for Bitcoin Core developers - jgarzik still has one (despite quitting Bitcoin Core ages ago), and gmaxwell also had one until a couple years ago.
@gmaxwell has a badge called
"Bitcoin expert" and there is no doubt that it is something permanent, although I have to admit that
@achow101 seems to have had a badge in the past that I can't see now (
Bitcoin-Qt core developer).
Bitcoin expert badge is basically for people who know so much Bitcoin that they could rewrite the protocol from scratch (without internet access too, I guess).