There is a commercially sold ERP solution that has it's DB schema in excel and Other documentations in MS Word. And its not even properly structured, no schema diagrams, last updated for a 4 year old major release 😒😫.
I have to develop a custom module for it and that requires building an ActivexDLL Project in VB fucking 6 😭😭 .

VB6
Unstructured Documentation
Legacy code
Incomplete documentation
FML

Tell me if you want ss in comments.