I wonder if this works as a heuristic. It seems like companies working with mature software would have less pretense, and so feel less need to gatekeep. Working with stuff like PHP or classic libraries and frameworks might signal they recognize they're just tools to get a job done, and it doesn't matter how you go about it as long as it's on time, on budget, meets the spec, and won't get them sued.
That's the classic library I had in mind. I could have been clearer. It's not perfect, but it's as good as any library would be after 15 years of changes to meet new needs.
>My worst tech interview experience: all of them.
Agreed. I thought it gets better. It doesn't. It gets way worse. Best jobs I interviewed for were around 2010 for jQuery and wordpress jobs.