Cannot invoke publishing on DITA OT project file containing "=" in its name - Windows

On Windows I have a file named something like "mobilePhoneProjectFile.xml=", I run the publishing on it:

dita -p D:/projects/dita/mobile-phone/mobilePhoneProjectFile.xml= -v
Searching for integrator.xml ...
Error: Project file D:\projects\eXml\samples\dita\mobile-phone\mobilePhoneProjectFile.xml does not exist

On Mac OS doing the same thing works.

Start by reproducing the Windows command `dita -p` with a DITA project filename ending in `=` and compare it with the same invocation on macOS. Trace how the project-file path is parsed before the reported existence check; done means Windows publishes the project successfully without changing the filename.

Written by the indexing model from the issue text.