Similar to T140804, this leads to unmaintainable code. Different extension stylesheets should not be sharing code in this fragile manner. However, there are imho two main use cases for this that we do want to keep:
* Using mixins provided by MediaWiki core (`mediawiki.mixins`).
* Creating interfaces based on the current skin or OOjs UI theme. We would define a standard set of variables and functions (with defaults) that skins and themes can override. Importing this `theme.less` or something, would automatically import the appropiate definition based on the skin for the current module context. Tracked as T112747.
These two use cases can be realised by providing those paths directly as import paths (not kept in a global configuration variable).
There are currently two uses of this variable:
* extensions/Flow (`flow.less`): Imports their own paths via the global import path (filed as T140806). Callers can be updated to point to the relevant directory directly.
* skins/MinervaNeue (`minerva.less`): Mostly the same as Flow, except there are a few callers in other repositories. Should be fixed by using ResourceModuleSkinStyles, or by using core's less variables instead (e.g. `@width-breakpoint-tablet` etc.), or, if skin-dependant, with T112747:
** [x] `MobileApp: /styles/links.less` (2016)
** [x] `Popups: /resources/renderer/LinkPreview.less` (2017)
** [ ] `CookieWarning: ext.CookieWarning.mobile.less` (2018)