1. Open ODP attachment 130922 [details] from bug 77552 (mistakenly attached to a report with a different topic)
2. Save as PPT or PPTX and reload
Text no longer has black outline, but is full-on black.
Tested with Win build from 15.09.2019 and 3.3.0.
One thing to consider just to be sure: does PowerPoint support text outline all the way to PPT binary format?
This is similar to bug #101569 which is about the import of the same thing.
In PP it's not character property but text outline effect (with line color, dashing etc. configurable), so a limited conversion should be possible.