org-export-before-processing-hook

org-export-before-processing-hook is a variable defined in `ox.el'.
Its value is

nil

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

Documentation:
Hook run at the beginning of the export process.

This is run before include keywords and macros are expanded and
Babel code blocks executed, on a copy of the original buffer
being exported. Visibility and narrowing are preserved. Point
is at the beginning of the buffer.

Every function in this hook will be called with one argument: the
back-end currently used, as a symbol.