Converting LibreOffice dialogs to .ui format, 200 conversions milestone

We’ve now reached 200 dialogs and tabpages converted from LibreOffice’s classic fixed widget size and position .src format to the GtkBuilder .ui format. These are still our own widgets, we just reuse the file format and map the Gtk widgets to our own equivalents. I’ve now finally refreshed the original sample screen shots to reflect the current reality.
I estimate we require an additional 200 to 400 .ui files, unless a lot of the existing .src dialogs turn out to be orphaned dialog descriptions that are not in use. (This is unlikely)
The How to conversion guide is still relevant, and help is appreciated.
Additionally, there’s a short list of selected dialogs awaiting review for any HIG compliance issues or general layout improvements. We have a python script as ./bin/lint-ui.py (thanks leighman) to check for basic compliance with guidelines, but there’s room for improvement, e.g. checking that widgets have mnemonic widgets, etc.