Dave friendica
I would not have predicted this would ever happen, but I've found a visual bell configuration that I actually like.
Dave friendica
I will note that this configuration *requires* information that the applications that try to force their preferred configuration on me cannot *possibly* know.
Dave friendica
I apparently need to find where Friendica allows specifying alt text. Image description: A screen grab of the MacOS terminal bell config; all of "Audible bell", "Visual bell", and Visual Bell's subfield "Only when sound is muted" are checked.
Tobias friendica (via ActivityPub)
Friendica is using BBCode for formatting of the postings @Dave for the ALT text of images, you can place the text in the middle of the [img][/img]-Tags. E.g.

[img=]And this would be the ALT text for the image used on mouse over etc.[/img]

Have a look at your nodes BBCode documentation for more information about the implementation of the BBCode in Friendica, and things like the "abstracts" which other parts of the Fediverse use for CW.