Telegram TData, Session, and JSON formats
A format name describes how a client session is stored; it does not guarantee lifetime, unrestricted use, or permission to break Telegram rules.
TData
TData is Telegram Desktop's local data directory. Treat it as a secret: copied state may include an active authorization and depends on client compatibility.
Session
A session file commonly stores state for a third-party Telegram client or library. Formats differ between programs, so the exact application should be named on the product page.
JSON beside a session
JSON often contains accompanying fields or exported parameters, but there is no single bundle standard. Read the product page and do not assume JSON replaces TData or a session file.
Safe first inspection
Use a separate clean environment, an official client where possible, and a recording from the first opening. Never upload a session to an unknown bot, converter, or extension; stop if you are asked to obtain someone else's code or bypass protection.