Data is a section in the Super Smash Flash series. It stores different settings between the two games.
In Super Smash Flash
In the original Super Smash Flash, data stores all are the game's records and other information. It includes an archive section that only hosts the "How to Play" section, a playable tutorial to learn the basic techniques of the game. Another section is Melee records, which is divided in Vs. records, which sorts individual statistics for each character like number of KO's, falls, self-destructions, damage given and taken, victories, etc., and Misc. record, which includes general game statistics like power time, play time, etc. The special section has all the special massages that show up whenever a task was accomplished, like clearing a game mode, and indicates a new feature is available, like a new character.
In Super Smash Flash 2
Data in Super Smash Flash 2 is a big departure from what it included in SSF. It no longer includes the game's records and statistics but the actual save data itself. Therefore, it only includes the options to export save data from the game, including options, records, controls, and unlocked content, in the form of a .ssfsav file that can then be imported to the game. The player is able to choose which data is exported from and imported to the game. The clear data option is found here as well. Players are also able to export data from previous revisions of the game in order to recover save data that may otherwise be lost.
Despite not holding any game's records at the moment, data's description in the main menu suggest it probably will.