org-link-abbrev-alist

org-link-abbrev-alist is a variable defined in `org.el'.
Its value is

nil

Documentation:
Alist of link abbreviations.
The car of each element is a string, to be replaced at the start of a link.
The cdrs are replacement values, like ("linkkey" . REPLACE). Abbreviated
links in Org-mode buffers can have an optional tag after a double colon, e.g.

[[linkkey:tag][description]]

The 'linkkey' must be a word word, starting with a letter, followed
by letters, numbers, '-' or '_'.

If REPLACE is a string, the tag will simply be appended to create the link.
If the string contains "%s", the tag will be inserted there. If the string
contains "%h", it will cause a url-encoded version of the tag to be inserted
at that point (see the function `url-hexify-string'). If the string contains
the specifier "%(my-function)", then the custom function `my-function' will
be invoked: this function takes the tag as its only argument and must return
a string.

REPLACE may also be a function that will be called with the tag as the
only argument to create the link, which should be returned as a string.

See the manual for examples.

You can customize this variable.