It's installed by hand for now (we're in the Chrome Web Store queue). Totally safe — it runs in your own browser, you do the checkout, no bots.
⬇ Download v1.0.2dropsync-extension-v1.0.2.zip to your Downloads folder. Keep this file — you'll need the folder inside it.dropsync-extension-v1.0.2.zip and choose Extract All… You'll get a folder named dropsync-extension-v1.0.2.chrome://extensions in the address bar, and press Enter. In the top-right corner, switch on Developer mode.dropsync-extension-v1.0.2 folder you unzipped → Select. DropSync appears in your list. (If Chrome shows a "developer mode extensions" note later, that's normal — just close it.)