Older versions of Spyder did not seem to have this problem but I'm currently running Spyder 6.0.6 and it does not let me run any files unless it has a recognized python extension. This is becoming an inconvenience as I am developing a python script tool for ArcGIS Pro that uses the .pyt extension. The only documentation I see at all on this is from another question that simply states you must use the .py extension found here Spyder 3.0 won't let me run file

I went to tools->preferences->Run and I see that I can set behavior based on file extensions but it seems to only let me use .py, .pyx, and .ipy.