>> 6. What will happen if I add/remove #+LATEX_HEADER in the buffer? in
>>    subtree properties? Are in-buffer latex settings supposed to affect
>>    anything? I tried to add #+LATEX_HEADER on top of the file, but the
>>    preview do not appear to be re-generated.
>
> Currently you need to set `org-latex-preview--preamble-content' to nil, which
> currently can be done by doing `C-c C-c' on the header / otherwise running
> `org-restart'.

It would be better to provide a command.
C-c C-c is too dramatic - it will reset much more than just preview
cache. (Like org-element-cache).

Or better add a new prefix arg to org-latex-preview that will force
re-generation.

Further, as discussed in the DM, we may need to consider that equation
preview may depend on latex export settings:

1. preview might be generic, utilizing "average" common latex preamble
2. preview might try to conform to latex export settings according to
   full document export
3. preview might use a different latex preamble when the current subtree
   will not actually be exported - like in commented subtrees. In
   particular, it matters for equation numbering
4. preview might try to generate preamble according to subtree export
   settings - some Org workflows involve multiple documents in one Org
   file, exported separately via subtree export.
   
-- 
Ihor Radchenko // yantar92,
Org mode contributor,
Learn more about Org mode at <https://orgmode.org/>.
Support Org development at <https://liberapay.com/org-mode>,
or support my work at <https://liberapay.com/yantar92>