You can download from releases
Enter path to your Dota 2 server log, default path on Windows is:
C:\Program Files (x86)\Steam\steamapps\common\dota 2 beta\game\dota\server_log.txt
Enter your Steam API key (if you don't have it yet, get it here).
Click 'Parse last match' button, wait 2-3 seconds and see what heroes people in your latest lobby played in the last 20 games.