The original GLTools was available as freeware in its basic form, with paid versions representing optional support for the developer. Users seeking the original GLTools functionality can often find legitimate free versions distributed through trusted channels like XDA Developers, though always verify the source's authenticity.
Newer versions, such as those adapted for Magisk, often come with the license pre-applied or use a GPL-2.0 license for open-source distributions. System Requirements for Licensed Use license key gltools