item.publicationTitle cf. https://aurimasv.github.io/z2csl/typeMap.xml#map-newspaperArticle

I'd be more comfortable if you implement a version of a getSearchResults function (using querySelectorAll instead of ZU.xpath, of course). These matches cover a broad set of pages and we really want to avoid false positives. There's a reason @zuphilip puts them in all translators.

Also, use .search(/regex/)!= -1 for efficient tests of strings against regexs

.search is more efficient than .match?

yes, because it just has to return true/false vs. an actual match. See https://jsperf.com/exec-vs-match-vs-test-vs-search/5 (indexOf is dramatically more efficient, so you could also use that for this one since you don't really need a regex, just three separate strings)

mozilla actually makes this distinction explicitin in the docs

When you want to know whether a pattern is found and also its index in a string use search() (if you only want to know it exists, use the similar test() method on the RegExp prototype, which returns a boolean); for more information (but slower execution) use match() (similar to the regular expression exec() method).

I poked around and it looks like test() becomes (15%) more efficient than multiple indexOf()s when comparing for multiple strings

(no need for an explicit return null or false here)

capitalize "snapshot" per convention.

use ZU.strToISO to avoid importing English dates into non-English locales.