Hi Eli,
Sorry for my misunderstanding for your preview comments.
> but wouldn't it be better to use symbols instead of strings?
The new option `dired-compress-files-default-suffix` can be “.tar.gz” or “.tar.xz”… and it should work with variable ` dired-compress-file-suffixes` while this variable maybe extended by user. So the type:string is simple for implementation.
And yes, the document need update, changes are available in the attachment.
Please help to review the new patch. Thanks.