volume shown on ToS traded is what?

lets say i see a volume of 536 calls traded on the 9:40 one minute candle as shown below (Volume: 536). my question is: are the 536 calls account only for the volume of these calls traded on ThinkorSwim (TDAmeritrade) accounts only? or is the 536 volume the total contracts traded for those calls across the entire market of exchanges?

blob:https://www.reddit.com/1787de1d-fbda-4ce7-a91f-a0d768ad830f

i think obviously its 536 calls traded across the entire market but i need to confirm with someone that knows this. thanks!