For those clients who couldn't possibly be walked through figuring out what is or isn't on their browser
https://www.whatismybrowser.com/
Hit "Detect" and then once done there's a form - they put in their email and yours and you get their browser details. Far fewer details than others I've seen, but a good way to get the info quickly
Scroll all the way down for the detailed info
It's also a brilliant email capture scheme. If you're selling a web dev product, what are the chances the "to" person is in your target demo?