Found the following significant warnings:
  DocParse.c:67:25: warning: '__xmlDoValidityCheckingDefaultValue' is deprecated [-Wdeprecated-declarations]
  DocParse.c:70:6: warning: '__xmlDoValidityCheckingDefaultValue' is deprecated [-Wdeprecated-declarations]
  HTMLParse.c:114:17: warning: '__xmlIndentTreeOutput' is deprecated [-Wdeprecated-declarations]
  HTMLParse.c:118:5: warning: '__xmlIndentTreeOutput' is deprecated [-Wdeprecated-declarations]
  HTMLParse.c:141:5: warning: '__xmlIndentTreeOutput' is deprecated [-Wdeprecated-declarations]
  HTMLParse.c:143:14: warning: 'use' is deprecated [-Wdeprecated-declarations]
  HTMLParse.c:152:67: warning: 'content' is deprecated [-Wdeprecated-declarations]
  RSDTD.c:121:9: warning: 'validate' is deprecated [-Wdeprecated-declarations]
  RSDTD.c:134:7: warning: 'xmlSkipBlankChars' is deprecated [-Wdeprecated-declarations]
  RSDTD.c:135:7: warning: 'xmlParseMarkupDecl' is deprecated [-Wdeprecated-declarations]
  RSDTD.c:555:67: warning: 'type' is deprecated [-Wdeprecated-declarations]
  RSDTD.c:556:41: warning: 'type' is deprecated [-Wdeprecated-declarations]
  RSDTD.c:559:72: warning: 'ocur' is deprecated [-Wdeprecated-declarations]
  RSDTD.c:560:39: warning: 'ocur' is deprecated [-Wdeprecated-declarations]
  RSDTD.c:563:12: warning: 'type' is deprecated [-Wdeprecated-declarations]
  RSDTD.c:566:19: warning: 'c1' is deprecated [-Wdeprecated-declarations]
  RSDTD.c:568:21: warning: 'c2' is deprecated [-Wdeprecated-declarations]
  RSDTD.c:573:16: warning: 'c1' is deprecated [-Wdeprecated-declarations]
  RSDTD.c:574:114: warning: 'c1' is deprecated [-Wdeprecated-declarations]
  RSDTD.c:578:18: warning: 'c2' is deprecated [-Wdeprecated-declarations]
  RSDTD.c:579:115: warning: 'c2' is deprecated [-Wdeprecated-declarations]
  RSDTD.c:583:15: warning: 'name' is deprecated [-Wdeprecated-declarations]
  RSDTD.c:585:113: warning: 'name' is deprecated [-Wdeprecated-declarations]
  RSDTD.c:589:16: warning: 'type' is deprecated [-Wdeprecated-declarations]
  RSDTD.c:620:36: warning: 'c2' is deprecated [-Wdeprecated-declarations]
  RSDTD.c:629:16: warning: 'type' is deprecated [-Wdeprecated-declarations]
  RSDTD.c:630:16: warning: 'c2' is deprecated [-Wdeprecated-declarations]
  RSDTD.c:636:65: warning: 'c1' is deprecated [-Wdeprecated-declarations]
  RSDTD.c:638:15: warning: 'c2' is deprecated [-Wdeprecated-declarations]
  RSDTD.c:642:18: warning: 'c1' is deprecated [-Wdeprecated-declarations]
  RSDTD.c:642:38: warning: 'type' is deprecated [-Wdeprecated-declarations]
  RSDTD.c:643:57: warning: 'c1' is deprecated [-Wdeprecated-declarations]
  RSDTD.c:645:16: warning: 'type' is deprecated [-Wdeprecated-declarations]
  RSDTD.c:646:16: warning: 'c2' is deprecated [-Wdeprecated-declarations]
  RSDTD.c:745:96: warning: 'tree' is deprecated [-Wdeprecated-declarations]
  RSDTD.c:777:16: warning: 'next' is deprecated [-Wdeprecated-declarations]
  RSDTD.c:786:71: warning: 'name' is deprecated [-Wdeprecated-declarations]
  RSDTD.c:787:18: warning: 'next' is deprecated [-Wdeprecated-declarations]
  RUtils.c:142:13: warning: 'xmlSubstituteEntitiesDefault' is deprecated [-Wdeprecated-declarations]
  XMLTree.c:1147:21: warning: '__xmlIndentTreeOutput' is deprecated [-Wdeprecated-declarations]
  XMLTree.c:1159:5: warning: '__xmlIndentTreeOutput' is deprecated [-Wdeprecated-declarations]
  XMLTree.c:1246:5: warning: '__xmlIndentTreeOutput' is deprecated [-Wdeprecated-declarations]
  XMLTree.c:1421:17: warning: '__xmlIndentTreeOutput' is deprecated [-Wdeprecated-declarations]
  XMLTree.c:1425:5: warning: '__xmlIndentTreeOutput' is deprecated [-Wdeprecated-declarations]
  XMLTree.c:1437:5: warning: '__xmlIndentTreeOutput' is deprecated [-Wdeprecated-declarations]
  XMLTree.c:1439:14: warning: 'use' is deprecated [-Wdeprecated-declarations]
  XMLTree.c:1442:105: warning: 'content' is deprecated [-Wdeprecated-declarations]
  XMLTree.c:1444:57: warning: 'content' is deprecated [-Wdeprecated-declarations]
  XMLTree.c:1539:18: warning: 'context' is deprecated [-Wdeprecated-declarations]
  XMLTree.c:1539:32: warning: 'context' is deprecated [-Wdeprecated-declarations]
See ‘/home/hornik/tmp/R.check/r-devel-clang/Work/PKGS/XML.Rcheck/00install.out’ for details.
* used C compiler: ‘Debian clang version 21.1.8 (3)’