So the basic idea is to configure httpd for making a proxy configuration file (.pac) available.

So far I'm on a very basic configuration only with the default configuration files:

CentOS 7.6.1810
Httpd 2.4.6 (yum installed - only the main package and its dependencies)

I created a pac file and used pacparser (https://github.com/manugarg/pacparser) to validate it.

Placed it in /var/www/html and edited /etc/httpd/conf/httpd.conf with:

<IfModule mime_module>
...
AddType application/x-ns-proxy-autoconfig .pac
...
</IfModule>

Restarted httpd. Started with no erros.
Browsing to http://<server>/proxy.pac asks for file download (Chrome, Firefox, IE and Edge).
Checking httpd's access.log shows the URL access correctly.

Now, when configuring the above URL inside any of those browsers for proxy configuration, nothing happens.
When I check httpd's access.log it shows nothing.

Any tips or directions on what could be wrong? Or maybe some other way I can try to debug this? I tried adding some DebugPAC lines into the pac file and then opening the browser's error consoles but nothing shows in there.
It seems that the script is not being executed.

Thank you very much for your time.

It's not necessary to use the "AddType application/x-ns-proxy-autoconfig .pac" in apache config. It's enough to specify the .pac URL in the client.
For example you can use the URL http://<server>/proxy.pac in firefox's "Automatic proxy configuration URL" setting, or start chrome using:
Anyway does the proxy specified in proxy.pac works and logs any access from these clients?

Actually, I just got back to it and now it just started working.