Optionalcustom_For 'custom_emoji' only, unique identifier of the custom emoji.
Optionaldate_For 'date_time' only, the string that defines the formatting of the date and time.
OptionallanguageFor 'pre' only, the programming language of the entity text.
Length of the entity in UTF-16 code units.
Offset in UTF-16 code units to the start of the entity.
Type of the entity (e.g. 'mention', 'hashtag', 'bot_command', 'url', 'bold', 'italic', etc.).
Optionalunix_For 'date_time' only, the Unix time associated with the entity.
OptionalurlFor 'text_link' only, URL that will be opened after user taps on the text.
OptionaluserFor 'text_mention' only, the mentioned user.
See
Telegram Bot API: MessageEntity