Currently, the software requires git version 1.8.5 or above. This is important as CentOS does not currently have a compatible version.

The issue is caused by the -C option which is used by report.php:

Line 19:

$rev = exec('git -C ' . escapeshellarg( $WPT_PREPARE_DIR ) . ' log -1 --pretty=%B | grep "git-svn-id:" | cut -d " " -f 2 | cut -d "@" -f 2');

Line 22:

$message = trim( exec('git -C ' . escapeshellarg( $WPT_PREPARE_DIR ) . ' log -1 --pretty=%B | head -1') );

node-sass seems to use it as well, but those are the only places where I see it being used.

Regarding the specific versions, you can see that the -C option (not to be confused with the -c option) was not present in 1.8.4.5:

https://www.git-scm.com/docs/git/1.8.4.5

It is present in 1.8.5, and versions after:

https://www.git-scm.com/docs/git/1.8.5

CentOS 7 (I am testing on 7.5.1804) has git version 1.8.3.1. However, I am also testing on a cPanel server, and when run using cPanel's git version, it is 2.19.1, which works fine.

I would recommend either adding the version to the software requirements, or perhaps looking at potentially removing the -C option if possible.