This seems fine.  Marking bug as Fixed and closing report.

I think the shorter text link is preferable.  If people want to go deep, then they can find more documentation.  But most people just want to quickly grab the basics.

haven't searched yet but assuming here's a doc location difference, we should point to PCRE or PCRE2?

Don't think this has changed in a decade. 

All mention of regexp appears to be located here:

https://docs.octave.org/latest/Searching-and-Replacing-in-Strings.html

Is this something we can add an external reference to address? If we are just implementing e.g., the posix standard I don't think the octave docs need to be a full regexp reference except to capture what is unique/different.

The documentation for regexp is missing some useful available features.  Here are some that I noticed.

1) Lookaround operators such as (?=), (?!), (?<=), (?<!)

2) POSIX character classes [[:class:]] where class might be "alpha" or "alnum" or ...

3) non-greedy (?) and atomic (+) adjectives for repetition quantifiers [*+?].

4) Backreferences in patterns such as \1 or \k<name>

5) Comments within patternns using (?# comment ) syntax

6) Discussion of escape sequence processing such as '\n' => newline.

7) Expanded discussion of named tokens

8) Conditional patterns based on prior subpattern capture