Tada, these things were left behind (Win XP Sp3 Admin):
HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\inkscape.exe HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\inkscape.exe\: "F:\PortableApps\InkscapePortable\App\Inkscape\inkscape.exe" HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\inkscape.exe\Path: "F:\PortableApps\InkscapePortable\App\Inkscape\python;F:\PortableApps\InkscapePortable\App\Inkscape\perl" HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.svg HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.svg\OpenWithList HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.svg\OpenWithList\a: "inkscape.exe" HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.svg\OpenWithList\MRUList: "a"