Exploratory testing has always been performed by skilled testers. Software testing can also be performed by non-dedicated software testers. Tests are created by developers and/or dedicated testers for each significant use case. Two writers and four testers were hired as contractors. Content was fine-tuned and updated daily throughout the test period based on testers feedback. Some advanced PAT testers can download information to a computer. Greenshot's feature set mainly targets project managers, testers and developers. There are various manufacturers of portable oil testers. The build number is an internal identifier used by Microsoft's developers and beta testers. This documentation may be used by developers, testers, and also end-users. Both of these two testings can be performed by users or independent testers. Around 3,000 beta testers on site provided feedback via QuakeCon. It included a demo mod made by several beta testers. DMX512 / RDM testers and configuration tools are available. The quality assurance is carried out by game testers.