In my org-mode documents I want to be able to write:
#+VAR: that_year=2020
and then somewhere in text use it like:
"And [[var:that_year]] we are going to..."
which should be interpreted and displayed like a regular link description, so looking at it should just be:
"And 2020 we are going to.."
Then later on when changing that_year=2020
to that_year=2021
all occurences in the buffer of the variable link to that_year
should also display 2021 instead of 2020.