While running install/install.py script in Debian, this error is encountered :
/home/darth_sidious/Documents/owtf/install/debian/install.sh: 53:
/home/darth_sidious/Documents/owtf/install/debian/install.sh:
/home/darth_sidious/Documents/owtf/install/debian/pref.sh: Permission denied
On further inspection of scripts under install directory:

It clearly states that install scripts under debian and samurai are not marked executable. These files must be marked executable and made available on upstream HEAD, so the developers need not mark them executable manually on cloning the repository, nor do they face merge conflicts as the executable bit of scripts on local machines is set while that of upstream isn't.
While running
install/install.pyscript in Debian, this error is encountered :On further inspection of scripts under install directory:

It clearly states that install scripts under debian and samurai are not marked executable. These files must be marked executable and made available on upstream HEAD, so the developers need not mark them executable manually on cloning the repository, nor do they face merge conflicts as the executable bit of scripts on local machines is set while that of upstream isn't.