Hi Wookey, thanks a lot for your comments.

1) Makefile and loch/Makefile (at least, maybe more) have been
converted from unix to DOS linefeeds. Thus breaking the patches. Was
that just an accident due to an over-enthusiastic editor? Is it going
to stay like that or can we agree whether the release is
DOS-throughout or unix throughout? (it's now a mix).

It is an error. It should be fixed in the updated archive on the server.

I see that the whitespace patch which fixed up a load of inconsistent
tab/space breakage has also not been applied: therion-5.3.12-whitespace.patch

I would like to fix it in the next release, together with all compiler warnings.
 
2) A couple of files are included that should not be:
samples/us.stackdump
thdb1d.cxx.orig
thbook/etc/contents.tex (that's a generated file, right?)
(this last was also in 5.3.15 so is not a regression)

Again errors. With exception of contents.txt - it is regenerated every time, but I am not sure, whether it can be removed.  
 
3) You have indeed included several of the debian patches (much appreciated),
but the upstream fixes in 20debianise-makefiles.patch have not been included:
(all in 'Makefile')

therion needs to be built before the samples can build:
-samples: $(OUTDIR)/samples.doc/index.tex
+samples: $(OUTDIR)/samples.doc/index.tex therion

windres does not exist on non-windows platforms (maybe macos?)
+ifeq ($(THPLATFORM),WIN32)
 $(OUTDIR)/therion.res: therion.rc
                        windres -i therion.rc -J rc -o $(OUTDIR)/therion.res -O coff
+endif

all the thTMPDIRs from the build need cleaning, not just the top one:
+   perl makefile.pl rmdir -q thTMPDIR samples/*/thTMPDIR samples/*/*/thTMPDIR
(that could be a find . -name thTMPDIR instead if you preferred a more general solution)

(I couldn't see this being fixed anywhere else, but maybe it has been?)

I will update this in the next release.
 
other patches not applied. Are there reasons why not?
* 82-nolang-segfault-fix.patch  (this avoids a genuine error case of language not being defined)

I believe, this error is already fixed. Are you able to reproduce it with current version of therion?
 
* 90load-extensionless-files.patch (fixes bug reported on this list a while back)

This needs to be done. 

* 2 hunks of fix-compiler-warnings.patch was applied, but not the other 19. Any reason?

No reason for that, will try to do it in the near future.

The remaining patches/hunks are debian-specific

Anyway packaging now updated and 5.3.16-1 uploaded to
experimental. (5.3.15-1 need to stay in unstable until the Debian
Freeze for the upcoming stable release is over, so new versions go in
experimental)

Feedback welcome, as ever.

Thanks again, S.