OK, it works better now. I installed python-pyside, updated mbarcode and plugins. The plugin appears in the list and outputs correctly to barcodes.txt, looks good.

The problem now is that the Results page appears even if the "Auto-run plugin" option is checked; not only this makes the workflow difficult (ideally you'd just run the camera over the barcodes with no other interaction necessary), but there is nothing to interact with on the page (I disabled all plugins except the isbn saver), it just stays there and doesn't respond to the back button either, so it needs to killed from the window switcher.

Attached is the stdout and stderr from mbarcode while it's started up, scans a barcode, looks for plugins, does its thing with the barcode, displays results and is killed from the window switcher.

Happy new year to all.