What email services support plus-addressing in email?

Question

Email

Good afternoon!
Some mail services support plus-addressing, for example, [email protected] and [email protected] are valid addresses. Some do not support, for example, a letter will never reach [email protected] .
Objective: Validate an e-mail that has one or more pluses in the recipient's name. It doesn't matter how exactly this character is processed by the mail server - it is cut off, an additional action is taken, or something else. It is important that the address is valid.
Question: Which email services support "+" and which don't?

Answer 1

fastmail.com
runbox.com