BOOTICE is a free and lightweight tool that allows users to configure and modify the low-level settings of their computer's boot process. The 64-bit version 1.3.3.2 you're mentioning is a specific release of this software.
Version 1.3.3.2 (64-bit) is notable because it was released during the cross-section of Windows 7 EOL and Windows 10 adoption, making it the last version to fully support legacy INT 13h extensions without requiring Secure Boot shutdown. bootice 64-bit 1.3.3.2
: It can fill a disk with specific data (like zeros) for security or testing purposes. BOOTICE is a free and lightweight tool that
While this version is pre-Grub2-full-integration, you can still use it to chainload: bootice 64-bit 1.3.3.2