I'm somewhat sad that they dropped the archive and subject fields (i.e. physics.optics). Those were really quick to grasp at a glance. And it seems they'll run out of numbers in about ten years, when monthly submissions reach six figures! (<a href="https://arxiv.org/stats/monthly_submissions" rel="nofollow">https://arxiv.org/stats/monthly_submissions</a>)<p>BTW, the link has a typo - it is <a href="https://arxiv.org/help/arxiv_identifier" rel="nofollow">https://arxiv.org/help/arxiv_identifier</a>