/usr/share/mimelnk/application/x-text-pgf.desktop is in ktikz 0.10-3build1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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Comment=PGF/TikZ drawing
Icon=/usr/share/pixmaps/ktikz32.xpm
Type=MimeType
MimeType=text/x-pgf;
Patterns=*.pgf;*.tikz;
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