Could you explain in more details what exactly you want to do. It will help me to find the proper solution.

Hi Diasy,
Thanks for your  help.

I have my own plugin that has various functions for admin and for registered users. Also, I would like to have a view for all (unregistered users).
My plugin doesn't have all standard permission functions via PRIVACY & PERMISSIONS page.
I just need simple solution for this one and only page to be visible to all and without any layout (TEMPLATE_BLANK ).

Kruno, I suggest that you download our new Plugin Skeleton plugin and check the Plugin installation/activation example to see it works.
Here is URL to the Store item: http://www.oxwall.org/store/item/695

Dear Daisy,
My whole plugin is complex and is in production already, and there are important data from my users. I'm afraid  that if I change install.php and deactivate plugin I will lose all information. Is that correct?

Is there any other option  to show just one page from this complex plugin to anyone and not touch install.php?

Thanks a lot,
Kruno

Kruno, if you did not add the functions which remove the plugin content into the deactivate.php file - simply add the necessary code to the activate.php file and reactivate the plugin.