diff --git a/required/latex-lab/latex-lab-math.dtx b/required/latex-lab/latex-lab-math.dtx
index 7c4cbfd62..400dcb3f9 100644
--- a/required/latex-lab/latex-lab-math.dtx
+++ b/required/latex-lab/latex-lab-math.dtx
@@ -233,32 +233,86 @@
%
% \subsection{Associated Files}
%
-% The current code allows to attach two type of associated files to the Formula structure:
-% the \LaTeX\ source and a MathML representation. Technically both can be attached---AF is an array
-% if file references---practically it could lead to problems with PDF consumers: from the
-% two consumer which handle AF-files, ngpdf uses both and so show the equation twice.
-% Foxit seems to see only the first AF in the array (which means that
+% The current code allows to attach two type of associated files to the
+% Formula structure:
+% the \LaTeX\ source and a MathML representation.
+% Technically both can be attached---AF is an array
+% if file references---practically there can be problems with PDF consumers as:
+% from the two consumer which handles currently AF-files, ngpdf used both and
+% so showed the equation twice (this has been corrected in the development version).
+% Foxit seemed to see only the first AF in the array (which means that
% the source code should be attached as second file.)
%
-% The \LaTeX\ source can be (and is) attached automatically. It can be suppressed by an option,
+% The \LaTeX\ source can be (and is) attached automatically.
+% It can be suppressed by an option,
% \texttt{texsource/AF=false}, see below.
%
% For a MathML representation a file with such representations must be provided.
+% If the equation is numbered the numbering should be part of the MathML as
+% the |Lbl| substructure is ignored if an MathML is used (see https://github.com/foxitsoftware/PDF_UA-2).
+%
+% Currently two input syntax for the MathML
+% are supported\footnote{We do not expect
+% both formats to stay. Experience will show which one is more useful and if more
+% adaptions are needed.}:
+% \begin{description}
+% \item[xml/tex-format]
% The file can start with \verb|| and end with \verb|| to make it a valid
% xml-file that can be validated.
+% It should have the extension \texttt{.xml}.
% The file should contain a number of representations in this format:
% \begin{syntax}
% \cs{mml}\Arg{key}\Arg{source}\Arg{hash}\Arg{mathml}
% \end{syntax}
%
+% The file is read in with the catcodes of \texttt{\#} and \texttt{\%} set to other
+% so that they can be used in the \meta{mathml}. But braces must be correctly balanced.
+%
% \meta{key} and \meta{source} are currently only used for debugging, they help to identify
% the equation referred by this representation. \meta{hash} is a hash key and is used
% to identify the equation to which the MathML should be attached. If the equation is changed
% it must be adapted. \meta{mathml} is the MathML representation.
%
-% By default the code tries at the begin of the document to read a file |\jobname-mathml.xml|.
-% The file name can be changed with |mathml/setfiles={filename1,filename2}| (without extension,
-% |xml| is added automatically). If there is a list, all files are loaded.
+% \item[\texttt{html}-format] A second format is meant to be a valid html file
+% to view and check the mathml representation of the math in a browser.
+% For this it can start with || and end with ||
+% It should have the extension \texttt{.html}.
+%
+% The file should contain a number of representations in this format:
+% \begin{quote}
+% |
| \\
+% |
\mml| \meta{key}|
|\\
+% |
|\meta{source}|
| \\
+% |
|\meta{hash}|
| \\
+% |
|\\
+% |
|
+% \end{quote}
+% The html tags ||, |h2|, |
|, |