This specific build introduced Task Manager improvements (live kernel memory dumps) and integrated OneDrive storage alerts in the Settings menu.
Modified ISOs are frequently injected with keyloggers, rootkits, or backdoors that bypass traditional antivirus because they are embedded directly into the OS kernel.
Build 25276 was an Insider Preview (beta), not a stable release. Using a beta version as your primary OS often leads to crashes, driver conflicts, and data loss. Official & Safe Alternatives