Following on from the post from uncle808us, viewtopic.php?f=139&t=153271 , I tried to preserve the vector graphics and text content of a simple .pdf file by opening it in Inkscape, exporting as a .svg file and then opening the .svg file in krita. As expected, this gave a grouped set of elements. so I tried to Ungroup it. This took a long time (if it ever finished) and gave a cursor in the form of a black hand, or a black double headed arrow depending where I moved it. If I waited long enough, then the ungrouping action seemed to finish and I could select individual vector elements. It was very slow however and usually crashed with the following error message:
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SAFE ASSERT (krita): "fuzzyMatrixCompare(leftOver, QTransform(), 1e-4)" in file /home/appimage/workspace/Krita_Release_Appimage_Build/krita/libs/global/kis_algebra_2d.cpp, line 591

Please report a bug to developers!

Press Ignore to try to continue.
Press Abort to see developers information (all unsaved data will be lost)
>

If I pressed Abort or Ignore then krita died. The file /home/appimage/workspace/ ..etc didn't exist when I looked for it.

Would a developer classify my actions as crazy/madness or is this something that needs to be investigated?
I can produce a link to let you download the .svg file if you like.