deckard could be used to preview translations of them.
Testing this out shows (as above) that it can be made to work. A few problems though:
1. We have various placeholder widgets which don't work in deckard because the widgets don't exist in gtk so dialogs that use them can't display as something falls over with e.g. "Invalid object type 'SvSimpleTableContainer'" I had hoped I'd get placeholders by default on failure.
2. Our .po translation entries for the dialogs strings all have autogenerated msgctxt fields which don't correspond to the blank default of the .ui so the msgctxt fields have to be removed, then msguniq to remove duplicates, and the result can the be run through msgfmt to create a .mo that works with deckard to show web-previews