It's because the link starts with "dev" but the security certificate is for wrongplanet.net, not dev.wrongplanet.net, so your browser will complain. This is as a result of errors during the update in 2014 which "polluted" the site's databases with some URLs of the form dev.wrongplanet.net.
It's nothing sinister, though - just remove "dev." from the URL in your browser's address bar and reload.
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Giraffe: a ruminant with a view.