About [[MediaWiki:Configure-setting-wgDBtestuser/en]]

Matma Rex, as said by Siebrand and Krinkle and iAlex before, this extension just copies the definitions on wiki, which in turn usually just copy code comments (in the first revision). You should edit the config pages directly and then commit fixes/improvements to the extension. I'm assigning this task to you, as you care about them and it's a wiki; speaking of which, if you're interested in translation of configuration variables documentation you should probably comment on mw:Thread:Project:Current issues/ Project:Translate extension. Thanks.

Fixed on mw:, I submitted gerrit change I14f5815a to fix this and other issues in the extension.