Found the following validation problem for the NEWS.Rd HTML conversion:
NEWS.html:52:1 (inst/NEWS.Rd:46): Warning: <h4> anchor "Bug-fixes" already defined
NEWS.html:83:1 (inst/NEWS.Rd:61): Warning: <h4> anchor "New-features" already defined
NEWS.html:98:1 (inst/NEWS.Rd:68): Warning: <h4> anchor "New-features" already defined
NEWS.html:113:1 (inst/NEWS.Rd:75): Warning: <h4> anchor "Documentation" already defined
NEWS.html:124:1 (inst/NEWS.Rd:80): Warning: <h4> anchor "New-features" already defined
NEWS.html:158:1 (inst/NEWS.Rd:96): Warning: <h4> anchor "Bug-fixes" already defined
NEWS.html:174:1 (inst/NEWS.Rd:104): Warning: <h4> anchor "Internal-changes" already defined
NEWS.html:189:1 (inst/NEWS.Rd:111): Warning: <h4> anchor "New-features" already defined
NEWS.html:207:1 (inst/NEWS.Rd:121): Warning: <h4> anchor "Internal-changes" already defined
NEWS.html:218:1 (inst/NEWS.Rd:126): Warning: <h4> anchor "Documentation" already defined
NEWS.html:233:1 (inst/NEWS.Rd:133): Warning: <h4> anchor "New-features" already defined
NEWS.html:249:1 (inst/NEWS.Rd:141): Warning: <h4> anchor "Documentation" already defined
NEWS.html:264:1 (inst/NEWS.Rd:148): Warning: <h4> anchor "New-features" already defined
NEWS.html:276:1 (inst/NEWS.Rd:154): Warning: <h4> anchor "Bug-fixes" already defined
NEWS.html:288:1 (inst/NEWS.Rd:160): Warning: <h4> anchor "Internal-changes" already defined
NEWS.html:300:1 (inst/NEWS.Rd:166): Warning: <h4> anchor "Documentation" already defined
NEWS.html:318:1 (inst/NEWS.Rd:174): Warning: <h4> anchor "New-features" already defined
NEWS.html:344:1 (inst/NEWS.Rd:188): Warning: <h4> anchor "Bug-fixes" already defined
NEWS.html:363:1 (inst/NEWS.Rd:197): Warning: <h4> anchor "New-features" already defined
NEWS.html:374:1 (inst/NEWS.Rd:202): Warning: <h4> anchor "Bug-fixes" already defined
NEWS.html:393:1 (inst/NEWS.Rd:211): Warning: <h4> anchor "New-features" already defined
NEWS.html:404:1 (inst/NEWS.Rd:216): Warning: <h4> anchor "User-visible-changes" already defined
NEWS.html:416:1 (inst/NEWS.Rd:222): Warning: <h4> anchor "Bug-fixes" already defined
NEWS.html:435:1 (inst/NEWS.Rd:231): Warning: <h4> anchor "Internal-changes" already defined
NEWS.html:459:1 (inst/NEWS.Rd:241): Warning: <h4> anchor "New-features" already defined
NEWS.html:485:1 (inst/NEWS.Rd:255): Warning: <h4> anchor "User-visible-changes" already defined
NEWS.html:506:1 (inst/NEWS.Rd:266): Warning: <h4> anchor "Bug-fixes" already defined
NEWS.html:522:1 (inst/NEWS.Rd:274): Warning: <h4> anchor "Internal-changes" already defined
NEWS.html:533:1 (inst/NEWS.Rd:279): Warning: <h4> anchor "Documentation" already defined
NEWS.html:549:1 (inst/NEWS.Rd:287): Warning: <h4> anchor "Bug-fixes" already defined
NEWS.html:572:1 (inst/NEWS.Rd:298): Warning: <h4> anchor "New-features" already defined
NEWS.html:595:1 (inst/NEWS.Rd:309): Warning: <h4> anchor "User-visible-changes" already defined
NEWS.html:626:1 (inst/NEWS.Rd:326): Warning: <h4> anchor "Bug-fixes" already defined
NEWS.html:641:1 (inst/NEWS.Rd:333): Warning: <h4> anchor "Internal-changes" already defined
NEWS.html:659:1 (inst/NEWS.Rd:341): Warning: <h4> anchor "New-features" already defined
NEWS.html:670:1 (inst/NEWS.Rd:346): Warning: <h4> anchor "Bug-fixes" already defined
NEWS.html:683:1 (inst/NEWS.Rd:353): Warning: <h4> anchor "User-visible-changes" already defined
NEWS.html:709:1 (inst/NEWS.Rd:365): Warning: <h4> anchor "New-features" already defined
NEWS.html:730:1 (inst/NEWS.Rd:376): Warning: <h4> anchor "Bug-fixes" already defined
NEWS.html:746:1 (inst/NEWS.Rd:384): Warning: <h4> anchor "User-visible-changes" already defined
NEWS.html:758:1 (inst/NEWS.Rd:390): Warning: <h4> anchor "Internal-changes" already defined
NEWS.html:806:1 (inst/NEWS.Rd:414): Warning: <h4> anchor "New-features" already defined
NEWS.html:836:1 (inst/NEWS.Rd:428): Warning: <h4> anchor "User-visible-changes" already defined
NEWS.html:857:1 (inst/NEWS.Rd:439): Warning: <h4> anchor "Internal-changes" already defined
NEWS.html:878:1 (inst/NEWS.Rd:448): Warning: <h4> anchor "Documentation" already defined