It seems to me that the only part to this answer that really addresses the question is the heading. OP claims to have been able to set up QPixel locally, so what you are talking about seems to not even apply. Also, what does specific licensing terms for content have to do with user authentication on an internal, locally hosted site?

Sorry, but this whole answer feels like a long non-sequitur.

I think (he have successfully build qpixel in his local system. Now, he wants to build a site with QPixel code). that's why I said that.

Even if I didn't ask about that, Istiak's answer adressed the fact whether (and possibly under which circumstances) we are allowed to fork the QPixel code. Moreover, he voiced concerns about my ability to implement this, which is valid, as I was asking (and hoping for) an easy setup just like any regular wordpress/drupal/phpBB/etc. site.

So, to me, his answer adressed the technical posibility to do so, while adressing and adding insight on my own incapability to do it on my own.

mw88‭ Except the advice given on using the code is incorrect. The relevant licensing information is in the LICENSE file in the source code. In particular, QPixel is distributed under the GNU Affero GPL license (AGPL). Creative Commons licenses are not designed for code and rarely used for it. They certainly aren't being used for QPixel's source code. You should read the license yourself, but, briefly, if you host a site using a modified version of QPixel then you must make the source of the modified version available under the AGPL. Using CC-BY 3.0 or CC-BY-SA 3.0 doesn't really make sense and is definitely not adequate nor necessary. Istiak is not in a position to grant you a different license.

Adding to what Derek Elkins‭ wrote above, while I am not a lawyer, for deleted user (or anyone else) to actually make the qpixel source code available under a different license would almost certainly be copyright infringement by way of offering something under terms not granted by the copyright holders.

That said, the content license for things which are hosted on and served by a qpixel instance, is an entirely different matter. The set of licenses available for posts is configurable; I don't know exactly where in the software, but that set is not fixed, and we've had some discussion here on Codidact on which licenses should be offered as choices. (Try searching Meta for "license".) If you want to host a qpixel instance that only allows the choice of, say, CC0 and CC BY-NC-ND, or CC BY-SA and the GFDL, or GFDL and MIT, or just CC0, or whichever other set you want to offer, that is entirely your choice.

Canina‭ Does MIT, Apache and other open-source allows to do copywrite "things"?

Edit :

COPYRIGHT
       Copyright  ©  2020  Free Software Foundation, Inc.  License GPLv3+: GNU
       GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
       This is free software: you are free  to  change  and  redistribute  it.
       There is NO WARRANTY, to the extent permitted by law.

found it from manual entry :rofl:

deleted user Absent copyright (I assume you meant copyright and not copywrite), generalizing somewhat, anyone can do anything with a work. In the presence of copyright and without an explicit license, again generalizing, only the copyright holder can do anything with a work. Copyright-based licenses allow the copyright holder to grant (some subset of or all) rights normally reserved to the copyright holder to another person or entity. A license builds on top of copyright and is dependent on copyright for its enforcement; a license is not a foundation for copyright.