What File to Edit to allow for more extension uploads?

what file can I update to allow other files to be uploaded through the interface? STL / OBJ / CURAFILES

What is the problem?

Cant upload original stl files

What did you already try to solve it?

None

Have you tried running in safe mode and if so did it solve the issue?

No

Complete Logs

Could not upload the file. Make sure that it is a readable, valid file with one of these extensions: .g, .gco, .gcode

Editing files to change things like this is not usually possible, since it is probably in the source code somewhere.
Try the 'Upload Anything' plugin:

My question here would be: Why? What do you plan to achieve? You cannot do anything from OctoPrint with any other file types than the ones already supported, unless you also install a slicer plugin, or some other plugin that knows what to do with further file types, in which case those plugins already do add support for the additional files.

This question sounds like someone is asking how to solve a problem they think they are having, when in fact they have a different problem.

The why is so simple. You ever use thingiverse? In there people save recipes in the zip file with the stl or they save pictures. I want to add my original stl files to the folder where I have my gcode files so if I ever use it on another printer or filament I can just go to octo and grab it.

In that case, the aforementioned plugin would help you.

We've had people come on here, asking how to upload STLs to OctoPrint because they expected to be able to directly print them without the slicing step in between, and then were upset when that didn't work as they expected and vented their frustration at us, so I hope you understand why I asked for the motivation behind this question.