I am trying to install grass7 addons locally.  I have downloaded them and am using the url=path version of the g.extension command line.  I get an error as follows:

    g.extension url=/home/user/source/grass7-addons/grass7/ -g
    List of available extensions (modules):
    Fetching list of extensions from GRASS-Addons SVN repository (be patient)...
    WARNING: Flag 'g' ignored, addons metadata file not available

I previously downloaded a metadata file from somewhere other than the svn repository.  I am trying to find it again (and I hope this question will make it easier to find in future).

Update:
I examined g.extension source. In the absence of the metadata file, it won't read the available extensions and won't compile them.  It was possible to compile extensions manually by setting the install directory for grass to world writeable, then compiling each extension manually:

    grass72
    sudo chmod -R a+w $GISBASE
    cd /path/to/extension/source
    make MODULE_TOPDIR=$GISBASE <extension_name>