A PR to fix markdown formatting has been created from this issue I raised https://github.com/syl20bnr/spacemacs/issues/15256 Essential, when pressing TAB in a table the formatting if the table would slip in some + characters, breaking the table when viewed on GitHub (e.g in a readme.md). This has been due to the inclusion of orgtabl-mode (which is excellent or org mode), however markdown now has its own features that orgtbl provides, so it's being removed from the markdown layer