The correct way to match a user agent?

[dtw]

I've been using the plugin for years but I have never been sure how to properly match a user agent. The use case is almost always that I just want to ignore 404s from specific crawlers. However, my attempts never work as expected.

If I want to ignore ALL 404s from this user agent (taken from my 404 list), for example:

Mozilla/5.0 (compatible; MojeekBot/0.11; +https://www.mojeek.com/bot.html)

I put a regex in the URL that matches everything:

.*

But what do I put in User Agent? Is the Redirect matching against the whole UA string or is "Mozilla/5.0" the only part Redirection looks at? Do I actually need a pretty complex regex that matches most of the string and accounts for version number changes?