Joplin does, and it works rather well. I have been planning on migrating my notes since the acquisition, but wanted to see what their next move was.
Joplin seems like the best at handling my mix of text notes, PDF files, and images at the moment. If it doesn't work out, though, at least I have my data in a more open form.
Standard Notes claims to, with a caveat that there may be a format it can't handle due to Evernote adding features.
A transfer-in from Evernote, either natively or through some third party utility, is a must. I'm not interested in writing something to parse .enex and put it into some other format (although .enex looks pretty easy to parse - it's xml with embedded BASE64 for some things like images).
