Gtk.TextBuffer.prototype.remove_tag_by_name

function remove_tag_by_name(name:String, start:Gtk.TextIter, end:Gtk.TextIter):void {
    // Gjs wrapper for gtk_text_buffer_remove_tag_by_name()
}

Calls Gtk.lookup on the buffer's tag table to get a Gtk.TextTag, then calls Gtk.TextBuffer.prototype.remove_tag.

name: name of a Gtk.TextTag
start: one bound of range to be untagged
end: other bound of range to be untagged