(Reply to Plasma/FAQ)
Consider the following examples: 1. Plasma/FAQ#How does Plasma work? links to the English page.
Special:MyLanguage/Plasma/FAQ#How does Plasma work? in any locale you will also be linked to the English page (broken localized links).
2. Plasma/FAQ/4.4/Configuration is valid page that can be linked, e.g. Plasma/FAQ/4.4/Configuration#Can_I_move_the_applets_on_the_panel.3F
On the other hand
Plasma/FAQ/Configuration#Can_I_move_the_applets_on_the_panel.3F points to nowhere (broken subpages).