From: openKylin Developers <packaging@lists.openkylin.top>
Date: Wed, 3 Jun 2026 14:02:48 +0800
Subject: debian-SDE-docs-in-tex-etex-manpage

---
 texk/web2c/man/etex.man | 14 ++++++++++++++
 texk/web2c/man/tex.man  |  8 ++++++++
 2 files changed, 22 insertions(+)

diff --git a/texk/web2c/man/etex.man b/texk/web2c/man/etex.man
index 8ff31c5..af1bbf3 100644
--- a/texk/web2c/man/etex.man
+++ b/texk/web2c/man/etex.man
@@ -327,6 +327,20 @@ is set when e-\*(TX is compiled.
 Search path for font metric
 .RI ( .tfm )
 files.
+.TP
+.B SOURCE_DATE_EPOCH
+If set, its value, taken to be in epoch-seconds, will be used for the
+timestamps in the PDF output, such as the CreationDate and ModDate keys.
+This is useful for making reproducible builds.
+.TP
+.B FORCE_SOURCE_DATE
+If set to the value "1", the time-related \*(TX primitives
+.RI ( \eyear ,
+.IR \emonth ,
+.IR \eday ,
+.IR \etime )
+are also initialized from the value of SOURCE_DATE_EPOCH.  This is not
+recommended if there is any viable alternative.
 .\"=====================================================================
 .SH FILES
 The location of the files mentioned below varies from system to
diff --git a/texk/web2c/man/tex.man b/texk/web2c/man/tex.man
index 07d744a..f55d91f 100644
--- a/texk/web2c/man/tex.man
+++ b/texk/web2c/man/tex.man
@@ -434,6 +434,14 @@ is set when \*(TX is compiled.
 Search path for font metric
 .RI ( .tfm )
 files.
+.P
+Notes for Debian developers: please keep in mind, that this version of
+the \*(TX interpreter ignores the
+.B SOURCE_DATE_EPOCH
+variable. Instead the current timestamp is written into the
+.I DVI
+file. If you need a reproducible time stamp, please use any engine based
+on pdf\*(TX, e.g., etex, pdftex, latex, pdflatex.
 .\"=====================================================================
 .SH FILES
 The location of the files mentioned below varies from system to
