Missing footer on first page of each chapter in LaTeX

In the doxygen pdf manual we see that on the first page of each chapter the footer is missing, the same occurs in the "normal" documentation generated by doxygen.
References:
- https://tex.stackexchange.com/questions/566034/footer-ruler-on-first-page-in-fancyhdr-with-book
- https://tex.stackexchange.com/questions/566056/footer-ruler-on-first-page-in-fancyhdr-with-book-but-not-in-part-part/

Code changes ("normal" documentation):
- latexgen.cpp changes required for the "normal" documentation

Code changes (doxygen manual)
- doxygen_manual.sty, remove word "Part" for the Appendices.
- manual.sty changes like for "normal" documentation plus patching part in case of the `\part` (here we don't want the footer or header)

Author: albert-github

doc/doxygen_manual.tex

@@ -171,6 +171,7 @@ \chapter{Internationalization}\label{langhowto}\hypertarget{langhowto}{}\input{l
 \chapter{Perl Module Output}\label{perlmod}\hypertarget{perlmod}{}\input{perlmod}
 \chapter{Doxygen's internals}\label{arch}\hypertarget{arch}{}\input{arch}
 \renewcommand{\thepart}{}
+\renewcommand{\partname}{}
 \part{Appendices}
 \appendix
 %mean that subinputfrom requires a / at the end of the path

doc/manual.sty

@@ -8,7 +8,6 @@
 
 % Setup fancy headings
 \RequirePackage{fancyhdr}
-\pagestyle{fancyplain}
 \newcommand{\clearemptydoublepage}{%
   \newpage{\pagestyle{empty}\cleardoublepage}%
 }
@@ -18,18 +17,28 @@
 \renewcommand{\sectionmark}[1]{%
   \markright{\thesection\ #1}%
 }
-\fancyhead[LE]{\fancyplain{}{\bfseries\thepage}}
-\fancyhead[CE]{\fancyplain{}{}}
-\fancyhead[RE]{\fancyplain{}{\bfseries\leftmark}}
-\fancyhead[LO]{\fancyplain{}{\bfseries\rightmark}}
-\fancyhead[CO]{\fancyplain{}{}}
-\fancyhead[RO]{\fancyplain{}{\bfseries\thepage}}
-\fancyfoot[LE]{\fancyplain{}{}}
-\fancyfoot[CE]{\fancyplain{}{}}
-\fancyfoot[RE]{\fancyplain{}{\bfseries\scriptsize Generated by Doxygen @VERSION@ }}
-\fancyfoot[LO]{\fancyplain{}{\bfseries\scriptsize Generated by Doxygen @VERSION@ }}
-\fancyfoot[CO]{\fancyplain{}{}}
-\fancyfoot[RO]{\fancyplain{}{}}
+
+% Headers & footers
+\pagestyle{fancyplain}
+\renewcommand{\footrulewidth}{0.4pt}
+%
+\fancypagestyle{fancyplain}{
+\fancyhf{}
+\fancyhead[LE, RO]{\bfseries\thepage}
+\fancyhead[LO]{\bfseries\rightmark}
+\fancyhead[RE]{\bfseries\leftmark}
+\fancyfoot[LO, RE]{\bfseries\scriptsize Generated by Doxygen @VERSION@ }
+}
+%
+\fancypagestyle{plain}{
+\fancyhf{}
+\fancyfoot[LO, RE]{\bfseries\scriptsize Generated by Doxygen @VERSION@ }
+\renewcommand{\headrulewidth}{0pt}}
+%
+\pagestyle{fancyplain}
+%
+\usepackage{xpatch}
+\xpatchcmd{\part}{plain}{empty}{}{}
 
 % Define caption that is also suitable in a table
 \makeatletter

src/latexgen.cpp

@@ -666,19 +666,24 @@ static void writeDefaultHeaderPart1(FTextStream &t)
   t << "% Headers & footers\n"
        "\\usepackage{fancyhdr}\n"
        "\\pagestyle{fancyplain}\n"
-       "\\fancyhead[LE]{\\fancyplain{}{\\bfseries\\thepage}}\n"
-       "\\fancyhead[CE]{\\fancyplain{}{}}\n"
-       "\\fancyhead[RE]{\\fancyplain{}{\\bfseries\\leftmark}}\n"
-       "\\fancyhead[LO]{\\fancyplain{}{\\bfseries\\rightmark}}\n"
-       "\\fancyhead[CO]{\\fancyplain{}{}}\n"
-       "\\fancyhead[RO]{\\fancyplain{}{\\bfseries\\thepage}}\n"
-       "\\fancyfoot[LE]{\\fancyplain{}{}}\n"
-       "\\fancyfoot[CE]{\\fancyplain{}{}}\n"
-       "\\fancyfoot[RE]{\\fancyplain{}{\\bfseries\\scriptsize " << genString << " Doxygen }}\n"
-       "\\fancyfoot[LO]{\\fancyplain{}{\\bfseries\\scriptsize " << genString << " Doxygen }}\n"
-       "\\fancyfoot[CO]{\\fancyplain{}{}}\n"
-       "\\fancyfoot[RO]{\\fancyplain{}{}}\n"
-       "\\renewcommand{\\footrulewidth}{0.4pt}\n";
+       "\\renewcommand{\\footrulewidth}{0.4pt}\n"
+       "%\n"
+       "\\fancypagestyle{fancyplain}{\n"
+       "\\fancyhf{}\n"
+       "\\fancyhead[LE, RO]{\\bfseries\\thepage}\n"
+       "\\fancyhead[LO]{\\bfseries\\rightmark}\n"
+       "\\fancyhead[RE]{\\bfseries\\leftmark}\n"
+       "\\fancyfoot[LO, RE]{\\bfseries\\scriptsize " << genString << " Doxygen }\n"
+       "}\n"
+       "%\n"
+       "\\fancypagestyle{plain}{\n"
+       "\\fancyhf{}\n"
+       "\\fancyfoot[LO, RE]{\\bfseries\\scriptsize " << genString << " Doxygen }\n"
+       "\\renewcommand{\\headrulewidth}{0pt}}\n"
+       "%\n"
+       "\\pagestyle{fancyplain}\n"
+       "%\n";
+
   if (!Config_getBool(COMPACT_LATEX))
   {
     t << "\\renewcommand{\\chaptermark}[1]{%\n"