Build error on a phantom file that is not in my sketch, but somehow created in AppData/Local/Temp\build on attempt to build  I get the following error

C:\Users\gmyer\AppData\Local\Temp\build5d24776aeb7b2efec3566cec737c36d8.tmp\sketch\trash\bootloader.c:1:1: error: unknown type name 'This'

 This modules tests receiving vacuum data from the

 ^


The problem is that I have no file of that name, and no text that exactly matches that any where in my sketch.  and my sketch is located in C:\Software

I have tried rebooting, deleting the Temp directory, reverting to known working code.  but it keeps regenerating.
I found the offending file in a sub directory of the C:\Software sketch directory.  I had a subdirectory called trash, and the Arduino build found it from there, and put it in AppData then referenced the error from there.