Thank you for your instruction.
I have used TortoiseSVN to download Source of WinMerge 2.7.4 finally. It is my first time to use it. I hope I will learn more about SVN slowly.
Setting "X-Poedit-Basepath" to "../../" is a good trick. Setting it to "..\..\" in Windows can work also. One can do that in Poedit (Catalog > Settings > Paths, Base Path: ../../) or edit the header information of .po.
> (Mm, where is Merge.rc in SVN?)
Since the source archives are build from the SVN files, the position
from the files are identical!
Main development always happens in the "Trunk":
The new translation system is testing in the "PO_translations_test" branch:
> * While editing MyLanguage.po right click on the strings in catalog and
> refer back to the strings one will understand the function of strings
> through the context. Reference is a place in source code where original
> string appears. It is neccessary for some strings to consult the meaning
> of original text with the source file.
The current PO files in the SVN branch "PO_translations_test" have all
the "X-Poedit-Basepath" set to "../../". In this case poEdit find the
source file in the upwards folders, if you don't change the folder