Maybe in /home/andy/.config/libreoffice... ?
Nope, nada for .xcu, reg, mod...
tm2t:~ # locate registry|less
tm2t:~ # locate registrymod|less
tm2t:~ # locate -i mod|grep -i regless
tm2t:~ # locate -i mod|grep -i reg|less
tm2t:~ # locate -i modifi|grep -i regist|less
tm2t:~ # locate -i modi|grep -i regist|less
tm2t:~ # locate -i modi|grep -i regis|less
From OpenOffice.org 3.3, thus in every version of LibreOffice,
registrymodifications.xcu is implemented to replace the older
../user/registry/ - tree of folders/files.
Hmmm. I am on:
LibreOffice 3.3.1
OOO330m19 (Build:8)
tag libreoffice-3.3.1.2
*locate -i registry* shows the tree
/usr/lib/libreoffice/basis3.3/share/registry
as well as a bunch of others, but no user tree and no
*registrymodifications.xcu* *anywhere.
I also tried
*find -iname registrymodifications**
just in case, with zero results.
No biggie, I now know how to control it (Go to full screen before
closing LO), so that is good enough for now. Thanks for your help and ...
TGIF!

Cheers, Andy
Doo doo doo doo... Twilight zone - cognitive dissonance....