Thanks for your question. The answer depends on the context in which you want to search.
In an [mla_gallery]
display you can add the post_mime_type
parameter to select one or more MIME types for the gallery.
In the Media/Assistant submenu table you can display the MIME Type as a table column, then click on one of the entries to filter the table by MIME type.
You can also create a custom view for the Media/Assistant submenu table. You’d first create a custom field with the MIME type values and then a custom view query on that field. If you put the mime type in a custom field you can also use that field to create a “filter by” dropdown in place of the Att. Categories dropdown on the Media/Assistant table.
Let me know which of those are of interest and what more specific help you need to implement your choice. Thanks for your interest in the plugin.