Doc https://www.yoctoproject.org/docs/2.7.1/bitbake-user-manual/bitbake-user-manual.html#bb-the-unpack describes a parameter 'basepath' "...to strip the specified directories from the source path when unpacking..." --> This functionality seems to be broken. Checking latest sources I found that this commit "bitbake: fetch2: fixes copying of file://dir; subdir=foo, bug 6128 and bug 6129" of Feb. 2016 seems to have removed handling of the respective parameter from source file bitbake/lib/bb/fetch2/__init__.py A grep in latest sources for 'parm.get(' shows hits for the other options unpack, dos, subdir but not for basepath. (This open question at stackoverflow seems to address the same topic, while referring to v1.6: https://stackoverflow.com/questions/50451961/stripping-base-path-off-the-unpacked-source-tree-with-bitbake-src-uri-file-fe?rq=1)
Patch sent to update the docs.
http://git.yoctoproject.org/cgit.cgi/poky/commit/?id=8c5b67bec26b653a392177a3bd528fced5cc8a15