Strange "tmp‏" folder in the root

Hi,
I had this strange folder when mine site was hacking, but I delete it.
Today, 5 days after site is cleaned and online with securitycheck pro, I see this folder again created.
But this time is empty.
Last time before I deleted it, inside this folder was two zip files.
tooltips-v3.7.9.zip
Joomla_3.3.x_to_3.3.6-Stable-Patch_Package.zip
Do someone know what is purpose of this folder?