The current support for abbreviations in home-fish-configuration is very limited, one can only specify the abbreviation name and expansion, or if determined enough, specify additional options like this:

--8<---------------cut here------------------------end--------------->8---

`(("--position anywhere abbreviation-name" . "expansion"))
--8<---------------cut here------------------------end--------------->8---

Which is quite weird, and gets weirder when additional options like marker, function, pattern and others are specified. The new abbreviation record type solves this issue, making abbreviation declaration more consistent with the usual Guix style.