removed extra extraneous comments

Cuts the multi-line rationale blocks down to what a reader of the file
needs. The reasoning behind the tagging setup belongs in the commit
messages that introduced it, not repeated above every \DocumentMetadata
block.

Also trims the README: drops the consequence clause explaining what
happens when the standard is declared without the tagging, drops the
quoted TeX Live 2024 error message, and notes that sid has a new enough
TeX Live for anyone not on Overleaf. Adds the caveat that a veraPDF
PASS is necessary but not sufficient, since a document whose body text
is all artifact passes too.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

README

@@ -50,13 +50,10 @@ All four templates build with LuaLaTeX (via latexmk -lualatex). The text
 fonts are Libertinus Serif and TeX Gyre Heros, both provided by
 texlive-fonts-extra.
 
-The paper, memo, and letter templates need TeX Live 2025 or later. The
-tagging code they rely on is not in TeX Live 2024, where the build
-stops with "the key 'document/metadata/tagging' is unknown". Debian
-trixie ships TeX Live 2024, so a trixie machine needs a newer TeX Live
-from elsewhere in the archive. On Overleaf, choose the TeX Live
-version under Menu > Settings > TeX Live version; 2025 or later is
-required and is not always the default for an older project.
+The tagging code requires TeX Live 2025 or later.  On Overleaf, set the
+version under Menu > Settings > TeX Live version.  Debian Trixie ships
+TeX Live 2024; sid (unstable) has TeX Live 2026, which also works and
+installs without pulling in much else.
 
 ================================
 === Accessibility ==============
@@ -65,15 +62,10 @@ required and is not always the default for an older project.
 The paper, memo, and letter templates produce tagged PDFs that declare
 PDF/UA-2 (ISO 14289-2). The poster template does not; see below.
 
-Tagging is switched on by the tagging=on key in the \DocumentMetadata
-block at the top of each template. That key is what does the work: it
-loads the kernel code that puts headings, paragraphs, lists, tables,
-and figures into the PDF's structure tree, which is what a screen
-reader walks. The neighbouring pdfstandard=ua-2 key only writes the
-conformance claim into the file's metadata. Setting the standard
-without setting tagging=on yields a PDF that announces itself as
-accessible and contains nothing for assistive software to read, so
-keep the two together.
+Two keys in the \DocumentMetadata block at the top of each template do
+this, and both are needed: tagging=on loads the kernel code that puts
+headings, paragraphs, lists, tables, and figures into the PDF's
+structure tree, and pdfstandard=ua-2 writes the conformance claim.
 
 The paper and memo templates were originally built on the memoir
 class, which is incompatible with the LaTeX tagged-PDF code. They now
@@ -85,62 +77,50 @@ Writing an accessible document
 ------------------------------
 
 Tagging gets you the structure; the content is still up to the author.
-Three things matter most, and the paper template carries a worked
-example of each:
+The paper template carries a worked example of each of these:
 
   * Use \section and \subsection for headings rather than setting type
-    in bold by hand. Screen reader users navigate by the heading tree,
-    and hand-formatted text is invisible to it.
+    in bold by hand. Screen reader users navigate by the heading tree.
 
   * Give every figure an alt= description on \includegraphics, saying
     what the reader is meant to take from it. A decorative image takes
-    \includegraphics[artifact]{...} instead, keeping it out of the
-    reading order.
+    \includegraphics[artifact]{...} instead.
 
   * Mark header rows on data tables with \tagpdfsetup{table/header-rows
-    ={1}} so their cells become TH rather than TD. Without it a table
-    reads as an undifferentiated grid of values.
+    ={1}} so their cells become TH rather than TD.
 
 Customizing the styles
 ----------------------
 
-Some common packages defeat tagging, and the failure is usually
-silent: the document compiles without complaint and the tags are
-simply missing. Before adding a package, check its status against the
-LaTeX Tagging Project's list:
+Some common packages defeat tagging, and the failure is silent: the
+document compiles without complaint and the tags are simply missing.
+Before adding a package, check it against the LaTeX Tagging Project's
+list:
 
   https://latex3.github.io/tagging-project/tagging-status/
 
-titlesec and titling are the two to know about here, because they are
-the obvious tools for the job cdsc-paper.sty and cdsc-memo.sty do.
-titlesec replaces the \@startsection hook that the tagging code uses
-to emit heading tags, so loading it produces a PDF with no headings in
-the structure tree and no error to say so. Both style files therefore
-build their headings and title blocks from the article class's own
-\@startsection and \@maketitle hooks.
+titlesec and titling are the two to know about, because they are the
+obvious tools for the job cdsc-paper.sty and cdsc-memo.sty do.
+titlesec replaces the \@startsection hook the tagging code uses to
+emit heading tags, so loading it produces a PDF with no headings in
+the structure tree.
 
 Verifying
 ---------
 
-Check a built PDF against the standard with veraPDF:
+You can check a built PDF with veraPDF (https://verapdf.org/):
 
   verapdf -f ua2 text.pdf
 
-It prints PASS or FAIL for the file, and --format text will list the
-clauses that failed. All four of the tagged templates pass as shipped,
-so a FAIL means something in the document needs attention rather than
-something in the template.
+It prints PASS or FAIL, and --format text lists the failing clauses.
+All three tagged templates pass as shipped, so a FAIL points at the
+document rather than the template.
 
-Run it. A document that declares PDF/UA-2 and does not meet it is
-worse than one that makes no claim, because the claim is what a reader
-relying on assistive software will trust. The declaration costs one
-line and validating it is the only thing that makes the line true.
+Note that a PASS is necessary but not sufficient. A document whose
+body text is all marked as artifact passes too, because the standard
+only requires that content which is not real be an artifact.
 
-veraPDF is not packaged in Debian; download it from
-https://verapdf.org/ and put it on your PATH.
-
-For a quicker look at whether a PDF carries any structure at all,
-without checking conformance:
+You can confirm there is something in the structure tree as well:
 
   python3 -c "import pikepdf,sys; d=pikepdf.open(sys.argv[1]); \
     print(d.Root.get('/StructTreeRoot') and 'tagged' or 'UNTAGGED')" file.pdf