Abbreviations are user-defined character sequences or words that are replaced with longer phrases after they are entered. For example, a frequently-run command such as `git checkout` can be abbreviated to `gco`. After entering `gco` and pressing @key{Space} or @key{Enter}, the full text `git checkout` will appear in the command line.
Abbreviations are stored using universal variables. You can create abbreviations directly on the command line, and they will be saved automatically. Calling `abbr -a` in config.fish will lead to slightly worse startup performance.