(not that i understand it too much, but...)
\+, a literal plus sign (the \ escapes any other meaning the + may otherwise have)
\d, signifies a digit, {14}, says 14 of them, digits, {1,14} would be a range of 1..14 digit(s) ...
?, oh, i don't remember, only that something funky was going on & the ? helped
\+ again a literal plussignhttps://www.geeksforgeeks.org/perl-regex-cheat-sheet/
(I had a different site that I used to go to, but I seem to have lost it from my browser history, & I'm not coming up with it again?)
Ah, here it is but only on googlecache ?,
PCRE Regex Cheatsheet.
And here it is (now) outside of cache,
JavaScript Regex Cheatsheet.
(Seems part of his site does not work properly in my browser.)