petersuber<p>2/ I suspect that these articles were published in <a href="https://fediscience.org/tags/paywalled" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>paywalled</span></a> journals. Their authors released preprints after publication as a way to avoid the risk of rejection (<a href="https://fediscience.org/tags/IngelfingerRule" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>IngelfingerRule</span></a>) and still make some version <a href="https://fediscience.org/tags/OpenAccess" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>OpenAccess</span></a>.</p><p>Depositing the accepted author manuscript (<a href="https://fediscience.org/tags/AAM" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>AAM</span></a>) in an OA repository (<a href="https://fediscience.org/tags/GreenOA" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>GreenOA</span></a>) would have let them share the peer-reviewed text, not just a preprint. But when journals don't allow this and when authors haven't retained rights, then depositing an OA preprint is a workaround.</p>