Notes for asymptote - reproducible builds result

Version annotated: 2.31-2
Identified issues:
Identifier: timestamps_in_png
Description PNG can capture build time with the tIME chunk or custom keywords.
These timestamps are currently removed by strip-nondeterminism, so are not visible to diffoscope anymore. Yet fixing the root cause would be nice.
Identifier: timestamps_in_pdf_generated_by_latex
Description PDF files generated with pdftex and pdflatex will contain CreationDate and
ModDate set to the current date and time.
Identifier: fonts_in_pdf_files
Description The internally used names/identifiers of fonts embedded into PDF files varies.
The order of embedded fonts can also be different.
The order is only different if the date differs (set by TZ environment
variable for example). If the date is the same, then the font name
is reproducible. Difference in hour/minute/second resolution seems
to be irrelevant.
The font name occurs in the /BaseFont field and in the /Fontname field.
The name is of the form XXXXXX+YYY where the XXXXXX part is the one that
varies and is called the subset_tag. It is generated in
texk/web2c/pdftexdir/utils.c function make_subset_tag() from an MD5 sum
over the font glyphs.
Identifier: random_id_in_pdf_generated_by_dblatex
Description eg.
/ID [<1ebdbec86dcab3e39cf225470b799ae8> <1ebdbec86dcab3e39cf225470b799ae8>]
Not caused by build path nor by the minute used to build at least.
Intermediate "--tempdir=docbuild" has no differences.
ID is varying because texlive generates it based on the build path, see also
pdf_id_varying_due_to_build_path issue.
(This might be tagged the same as random_order_of_pdf_ids_generated_by_latex)
Comments: Content of PNG file is also differing.

Our notes about issues affecting packages are stored in notes.git and are targeted at packages in Debian in 'unstable/amd64' (unless they say otherwise).