Prebuilt nginx modules (configuration)?

[tgkprog]

hello, I have a few questions:

A. I want to install nginx on a seperate directory on my Ubuntu 14.04 LTS.
Can I use the pre built version for that? How do it? Download the deb and
run the command from terminal with the
--prefix=/home/wibmoapp/apps/ngx/n1_12_0 option?

B. Else do I need to build from source? I'm able to build from source, but I
want to know what are the exact modules that are included in the pre built
Ubuntu version, where can I see that?

C. If I want to use debug option with pre built, installed on a seperate
directory, what are the steps? In the Packages file
(http://nginx.org/packages/mainline/ubuntu/dists/trusty/nginx/binary-amd64/Packages)
I see 
Filename: pool/nginx/n/nginx/nginx-dbg_1.9.0-1~trusty_amd64.deb
Size: 1217282

So is this a fresh install or an add on?
Need to back up config, install this and then re apply config?

thank you very much.

Posted at Nginx Forum: https://forum.nginx.org/read.php?2,274507,274507#msg-274507