In pre-flight checks, also consult open PR queue

doc/5.x-final.md

@@ -16,6 +16,7 @@ git push origin 5.X
 
 ## 2: Sanity checks
 
+* Check open PRs for `5.X`: https://github.com/civicrm/civicrm-core/pulls
 * Check release notes: https://github.com/civicrm/civicrm-core/tree/5.X/release-notes
 * In Jenkins, review the scheduled tests for `5.X` and determine if anything should block the release.
     * https://test.civicrm.org/job/CiviCRM-Core-Matrix/

doc/5.x-patch.md

@@ -27,6 +27,7 @@ git push origin 5.X
 
 ## 3: Sanity checks
 
+* Check open PRs for `5.X`: https://github.com/civicrm/civicrm-core/pulls
 * Check release notes: https://github.com/civicrm/civicrm-core/tree/5.X/release-notes
 * In Jenkins, review the scheduled tests for `5.X` and determine if anything should block the release.
     * https://test.civicrm.org/job/CiviCRM-Core-Matrix/