SlowValue

creating a virtual machine build environment so I didn't have to litter my main computer with 100s of packages to build emacs.

That's is a good idea! Despite what all others say. I'm doing this since years with my Linux box(es).

But you need to know, that self compiled programms should be stored below the filesystem tree /usr/local/.
There is a tool called stow, it has a package in most Linux distributions.
Install stow into host and VM and create a directory /usr/local/stow/ in both (host an VM).
When compiling Emacs or other programs use the --prefix option of configure. E.g. cd emacs-src; ./configure --prefix=/usr/local/stow/emacs-v29.1. Then compile Emacs and install it in the virtual machine. After that, tar the folder /usr/local/stow/emacs-v29.1 and unpack it onto the host into the same directory. Then change dir into /usr/local/stow and run sudo stow emacs-v29.1. Maybe you need to install some libraries onto the host, use ldd /usr/local/bin/emacs to see, what libs you need. Then you are ready to use emacs. It is possible to have multiple versions of emacs installed and only one needs to be "activated" via stow.

Thanks for your answer, though it does not help me with the issue (read below , why). I updated my question with screenshots.

What you call online documentation is just the package manual.

I wrote "on-line" within quotation marks. What I called "on-line" documentation is the function documentation (aka docstring). But I feared, when I would use function documentation every one would point me to the official calc manual ...
"On-line documentation" is (imho) just 1980s terminology for documentation readable within the program.

[...] helpful [...] puts links to the calc manual in the function documentation [...].

I updated my Question with screenshots, those screenshots are intended to make it more clear. Using helpful's WWW link in an emacs help buffer is like walking to the public library and reading a book (for my intended use case). (Don't get me wrong, reading a book from a public library is nice, I'm glad such things are possible.)

Thanks for the explanation, that possibility did not cross my mind, since I'm used to use swiper. :)

TIL
So then it is / n.

Let me cite RMS to answer that:

The editor itself was written entirely in Lisp. Multics Emacs proved to be a great success—programming new editing commands was so convenient that even the secretaries in his office started learning how to use it. They used a manual someone had written which showed how to extend Emacs, but didn't say it was a programming. So the secretaries, who believed they couldn't do programming, weren't scared off. They read the manual, discovered they could do useful things and they learned to program.

source: https://www.gnu.org/gnu/rms-lisp.html

Programming in elisp is fun, too. Since it's (typical for Lisp!) interactive programming features.

What is the meaning of that?
Just typing this at the swiper prompt searches for /-n....

This is for documentation, in case someone else has a similar problem.

I sort of worked around Emacs weird choosing of fonts, since I do not know the real problem. Maybe it is a bug?

I put following in my init.el (I'm not fully satisfied, yet):

  (set-fontset-font "fontset-startup" '(#x2190 . #x21fe) "-misc-fixed-*-*-*--*-*-75-75-c-60-iso10646-1") ;; unicode arrows
  (set-fontset-font "fontset-startup" #x2026 "-misc-fixed-*-*-*--9-90-75-75-c-60-iso10646-1") ;; the …

Docs say it is possible to define a fontset in .Xresources, but I did not try.

You can check your current fontset via M-x describe-fontset.

My configuration uses fontset-startup primarily and fontset-default as fallback. So I modified fontset-startup.

The codepoint for characters (required second parameter for set-fontset-font) can be retrieved via C-u C-x =. All that is documented in the Emacs manual, btw.

Test if those settings work, by opening a org-mode buffer and using bold (*TEST*) and italic (/TEST/) on characters you want to test.

Not sure how plain ivy sorts its candidates, but do you have by chance any additional package installed? A package, which re-sorts the candidate list? A Package like prescient, smex, flx, historian, ...?

regarding Elisp:
Consider using and contributing to the packages helpful and/or elisp-demos.

Here is a video showing two more variants:

https://0x0.st/HJF3.mkv

Yes isearch is powerful, but you have to learn and remember its keybindings, because if you don't: isearch quits (and I need to start that search at the beginning).

Isearch's help C-h b doesn't make it better, because I would need to scroll that long list in the help window, but if I do so .... isearch quits.

Therefore I installed the package isearch-mb (*) and used easy-menu to add a drop down menu for isearch. Now, if I can't remember an isearch keybinding, I am able to look at the menu bar, without isearch quitting.

(*) As always with Emacs: there are other ways to solve that.

thanks!

I found this: https://lists.gnu.org/r/bug-gnu-emacs/2023-07/msg01135.html

From above link:
Those files have set no-byte-compile to t, but Emacs needs to open those files (and reports it) in order to see this setting.

So, setting native-comp-jit-compilation-deny-list won't do any harm here. I will use it to suppress this messages.

You got me interested, but I never worked with ob-plantuml before. I'd like to try it myself.

Could you please give a full working example? One with org-block arguments and working export to latex/pdf.
Or link a tutorial?