Where does .gltf come from?

when making a 3D model, you need to use a .gltf file. I am a rookie. I want to know who provided this file, whether it is designed or processed in the background

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Mar.22,2021
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b3e50a-2c3e7.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b3e50a-2c3e7.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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