Help needed with SfxItems mentioned in .sdi files

In <https://gerrit.libreoffice.org/#/c/34775/> "Complete the transition 
of SwRedlineTable::size_type" I have the following question:

"TODO:  The one place I'm unsure about is SfxUInt16Items with IDs 
FN_REDLINE_ACCEPT_DIRECT, FN_REDLINE_REJECT_DIRECT, and 
FN_REDLINE_NEXT_CHANGE in sw/source/uibase/uiview/view2.cxx.  For now, I 
kept those as SfxUInt16Items and take care to "map" USHRT_MAX to npos 
when reading from those items.  But I have no idea where instances of 
those items would actually be created, and what it would mean to change 
those items' types?"

Those FN_REDLINE_* are mentioned in sw/sdi/{_viewsh,swriter}.sdi, and 
those .sdi files are a great mystery to me...