Why would you use a protocol-relative URL to link to translatewiki.net? I thought protocol-relative URLs were just a hack to support HTTPS proxies without cache variance. You can see from the squid logs that they break lots of clients. If you prefer https, why not just link to https?
We added protocol relative URLs for all sites that are using both http and https. Twn is just one of those. Would you prefer that all sites outside of Wikimedia just used protocol specific URLs, possibly with a preference for https?