And it came to pass, when kol hamelachim which were beyond the Yarden, in the har, and in the Shefelah, and in all the coasts of the Yam Hagadol [i.e., the Mediterranean] over against the Levanon, the Chitti, and HaEmori, the Kena'ani, the Perizzi, the Chivi, and the Yevusi, heard thereof; (Yehoshua 9:1 OJB)
And the same in the HCSB:
When all the kings heard [about Jericho and Ai], those who were west of the Jordan in the hill country, in the Judean foothills, and all along the coast of the Mediterranean Sea toward Lebanon-the Hittites, Amorites, Canaanites, Perizzites, Hivites, and Jebusites- (Joshua 9:1 HCSB)
So it seems Shefera means "Judean foothills."
Note: I'm getting the spelling "shefera" from Google Translate.