As the software was released to the public free of cost and its from NSA, common comments we get over some YouTube videos are this question title.
Is there any sort of Backdoor or Any other Monitoring Services in the Software ?
It's going to be open-source on the full release, so you can inspect and compile the code for yourself.
If someone finds something related to this topic, what will be the NSA's reply?
A strikingly similar question was asked and answered on https://github.com/NationalSecurityAgency/qgis-searchlayers-plugin/issues/6#issuecomment-367773492
In short:
They said in their talk that there are no backdoors in this application, but you can always just decompile it and look for yourself until the source is out.
Most helpful comment
It's going to be open-source on the full release, so you can inspect and compile the code for yourself.