I'd argue that this is a resume overindexed on getting past recruiting filters looking for specific JavaScript libraries or UNIX commands. Even the recruiters action may not be necessarily bad - startups with a decided tech stack might decide they are not able to provide the time for a new hire to ramp up.

Effectively you penalise not catering the candidate resume to what you are looking for or deem important.

Does anybody even know anything about these resume filters? They seem legendary, or I'd think there would be a best practice by now.

The trick is there are multiple resume filters.

One will filter you out for having too many keywords. One will filter you out for not having enough keywords. One will filter you out for including a picture. One will filter you out for not including a picture. One will ... ad infinitum

Your resume is being evaluated by different filters constantly. Different filters filter different things. There is no "right" answer. There are only answers you will or won't be filtered out for depending on which filter is being applied.

Which filter is being applied?

It's random.

Hiring is essentially random.

Various vendors of software in that space claim they are best practice, e.g. IBM: https://www.ibm.com/talent-management/hr-topic-hub/applicant..., https://appsource.microsoft.com/en-us/product/web-apps/cem_b... promotes keyword matching as a feature, ...

Oh sure, I know they exist, but on the resume side there's no common knowledge of anything besides keyword stuffing. I'm wondering if that's actuallly the best way given how the filters actually work (which I don't know).

Algorithmic HR has ruined any chance you won't see an SEO centric resume ever again.

"I need my resume to show up in your filter, relevance to the actual job functions be damned."