"Building a theme" tutorial still up to date? [SOLVED]

[Scindix]

Hi community,
I wanted to dig into writing themes. Google led me to the following site: https://developer.mozilla.org/en-US/docs/Building_a_Theme. However I'm wondering if the site is still up to date.
First I couldn't get the "hello world" theme from the tutorial working. I already posted a question at stackexchange, but got no answer. (See here: http://stackoverflow.com/questions/39648677/firefox-newly-created-theme-following-tutorial-doesnt-change-anything-in-the)
After discovering that the aforementioned tutorial has been tagged with "NeedsUpdate" I have serious concerns that this article is outdated. Am I right with this assumption? If yes, where can I get a good tutorial about writing complete themes in firefox?

[Scindix]

Okay now it gets really strange. I unzipped another theme from the Firefox extensions site that works and currently is also enabled. I changed the name and the id in the install.rdf file saved it, removed the META-INF folder (as Firefox thinks it is corrupt otherwise because of the mismatching hash sums) and zipped the xpi file again. When loading the plugin file Firefox says that this plugin is incompatible with "Firefox 49". However in the install.rdf "maxVersion" is set to "50.*"

Code: Select all

<em:maxVersion>50.*</em:maxVersion>

I replaced the install.rdf with the file from the tutorial. Now Firefox accepts the plugin although the exact same code line above is present here as well. (maxVersion is set to 50.*, too!) Nevertheless the symptoms are exactly the same as in the hello world tutorial. Firefox shows the standard theme instead of the copied theme. How could that be? I only changed the meta information and set a new id. Other than that the theme is exactly the same. Could it be that Firefox needs the META-INF folder to properly load the theme? How can I create it? I somehow wasn't able to recreate the hash sum of install.rdf in manifest.mf by hand.

[Scindix]

The third column needs to match your theme's internalName value from the install manifest above.

I copy-pasted the contents of chrome.manifest from the tutorial to my file.

That was it. I forgot to adjust "sample" to the internalName I was using in my install.rdf