org-tab-first-hook

org-tab-first-hook is a variable defined in `org.el'.
Its value is

(org-hide-block-toggle-maybe org-src-native-tab-command-maybe org-babel-hide-result-toggle-maybe org-babel-header-arg-expand)

• This variable may be risky if used as a file-local variable.

Documentation:
Hook for functions to attach themselves to TAB.
See `org-ctrl-c-ctrl-c-hook' for more information.
This hook runs as the first action when TAB is pressed, even before
`org-cycle' messes around with the `outline-regexp' to cater for
inline tasks and plain list item folding.
If any function in this hook returns t, any other actions that
would have been caused by TAB (such as table field motion or visibility
cycling) will not occur.