Cletus-:
Thank you very much!
Sorry, I cannot understand, what does it mean?
So it sounds like you cannot just copy a template folder, e.g. "responsive_classic" or "winchester_black" and rename it to "responsive_classic_2" or "winchester_black_2" in the templates folder: \includes\templates\responsive_classic_2. So simply clone the entire template folders does not appear to work, that's why one should use that plugin.
And which files are overrideable or not shows that plugin or, I assume, it works for folders only.
So for example to \includes\templates\responsive_classic_2, respectively to a sub folder.
I would try to get a consistent design / look, so I would change for example the colors of all pages effecting all devices, e.g. the same background color for every device.
I would have supposed a responsive template automatically adapts the display to the different devices. So there would be no need to change anything regarding the size of the screen.
And after each update you have to check the (possibly) updated (template) files if they contain new code / functions which one would have to copy to the modified (css / template) files?
So not modify the files which might / will be overwritten when updating the next time.
Sorry, what does "operational view" mean? A (unsightly) look of the shop caused by missing / overwritten css files or so by the latest / an update?
It turns out again being much more complicated as I had expected.
Many thanks, again
Historically the classic template had minimal modifications in all of the template override folders. There are some specifically in the includes/templates folders but there are many template override folders/areas for each template. So, now there is a responsive template that is built in, but in order to support its functionality more files require modification than the older classic template. Therefore the statement of "how it is". The functionality added to the site is basically dependent on those additional files not just an addition to the existing template_default related files.
You can "just" copy a template override folder, but you have to do it in every location where that template overrides a file. It is possible to do manually, but the plugin makes it more automated/easier. It doesn't support making that type of copy from one store to another, but it does make it easier within a given store. There are some other changes needed when manually making the copy, but I thought that was covered in the link you provided in your OP.
The overrideable files/folders are shown in a separate "plugin" (set of files downloadable from the plugins area but are intended to be viewed at your local computer as a sort of "help" file.) called something like template override cheatsheet. I would not expect that the plugin would provide that same level of "discussion".
For color changes only, I would suspect that all displays of the template would likely use a single source; however, it is always possible to modify any aspect of the displayed information to suit a specific need. As such and perhaps responsive templates are not understood, but generally speaking the css files contain screen resolution break points. For screens with a resolution X, the following css is to be different than the "standard". This resolution is to what I referred as screen size. Well, now, or more recently the responsive design concept has been taking into account the type of device and as part of that loading different css files. So, there runs the possibility that a change made to the tablet file with resolution less than 1024 x 786 may not show under the mobile file with the same resolution. There comes the "art" of css and the front side development of a site. Then even within a single file, different devices of the same type may render the display differently. Again a factor to consider based on the needs/expectations of the site operator, the current technology, and the ability to detect/control that display.
Regarding the end of questions. It seems as if you understand, work on files in a template override directory (where such possibility exists), the files being overridden are generally expected to be present in the next version of ZC and the team seems to painstakingly keep it that way to make upgrading and interoperability easier, when doing the next upgrade, review changes made to the underlying/overridden files (and associated files as well) to determine what if anything needs to be modified to "restore" the site back to its former glory but including the new functionality/improved security. This last part is one of many specific reasons that a site should be developed and modified outside of the live site with the improvements applied in a controlled stable manner.
Yes, there are many steps involved, but the goal is to maintain a productive site, do the best that can be done to make future upgrades easy as possible, possibly identify areas of the code that could use improvement to make it that much better and to make any such improvements portable to others/other sites wanting that same functionality.
Can a single minor change be made to one of the existing files so as not to go through that process of duplicating the template file(s)? Sure, but should continue to consider, how many such small changes can be made before the overall changes are more significant? :) That's where planning and maintenance come in to play.
