If the "(Install)" tag refers to a installer (common in Nexus Mods), the most important text file is the XML script that governs the installation menu. It contains:
Almost all "Ultimate" texture packs include a plain text file containing: ULTIMATE_4K_Textures_PT4(Install).zip
A list of artists or original sources for the 4K assets. If the "(Install)" tag refers to a installer
If you downloaded this file from an unverified source (like a random file-sharing site rather than an official modding hub), be cautious. Large "Ultimate" packs are often used as wrappers for malware. I recommend scanning the .zip with VirusTotal before running any executable or "install" script inside. ULTIMATE_4K_Textures_PT4(Install).zip