Hello, I am new on HA. I have a KNX automated house. To integrate the whole in HA I have a KNXPROJ file … but not the password. Is there any way to find it? Many thanks in advance.
Ask the one who did set the password 
Other than that, a .knxproj file is essentially a Zip-file containing a password protected zip file. So anything able to find a zip-file password should do it - searching for such a tool may probably yield more results.