It's documented in svn help log
and svn help status
:
--incremental : give output suitable for concatenation
It means don't generate the outermost elements in XML mode, i.e. rather than
<?xml version="1.0"?>
<log>
<logentry> ... </logentry>
<logentry> ... </logentry>
</log>
which generates a complete, well-formed XML document, just generate
<logentry> ... </logentry>
<logentry> ... </logentry>
so that you can concatenate multiple svn log --xml --incremental -rX:Y
outputs together, i.e.
svn log --xml --incremental -r 1:1000 > log.xml
and
svn log --xml --incremental -r 1:250 > log.xml
svn log --xml --incremental -r 250:500 >> log.xml
svn log --xml --incremental -r 500:750 >> log.xml
svn log --xml --incremental -r 750:1000 >> log.xml
will generate exactly the same output.