TimotheeMathieu

From what I see it is meant to act on TODO, but with your code I don't see anything changing for TODO's. I tried with and without `begin_src` svg-tags.

No I see no change. I am not sure what your code was meant to do but I guess you wanted to test that the TODO became an svg but...

I tried and indeed this replaces TODO with WORKS. It works, as you said it should. Also, I have SVG support because if I just use the usual TODO svg...

Yes. This one works and transform the language of the source code in an svg with TEST written in it: 

I tried it: I got the message `Tag value: emacs-lisp` in the messsage buffer for my emacs-lisp source code but on the other hand, the text was without any font...

Yes. I added the code to the init.el and when I do `M-x svg-tag-mode` while in the org-mode file, the font-lock disappear from my test org-mode file and I get...

This works, transform the lisp to LISP when executed and message is `(jit-lock-bounds 1 . some-number)` with the some-number being an integer different every time I execute.

I tried to change the library with some intuition of what things should do, but I am really not fluent enough in elisp and in particular in font lock to...

I was also interested in this feature and I managed to do it after some tests. Here is the code heavily copy-pasted from org.el, it can most definitely be improved...

Update: I found that an even better solution is to use poly-mode. By making a polymode for ob-tmux I was able to get, in addition to proper syntax highlighting, also...