Since this is a third-party utility not hosted on official app stores, it is primarily available through community-driven developer forums and GitHub:
The tool is frequently reshared on sites like AndnixSH. Download Split APKs Packer app for Android zip
A versatile manager that can extract installed apps and compress them into a zip file for backup. Since this is a third-party utility not hosted
You can often find the latest builds on release-apk.com (registration may be required). Download Split APKs Packer app for Android zip
If you are looking to or extract split APKs directly on your Android device rather than merging them into one file, these apps are more standard:
A similar open-source bash script to combine split APKs is available on TheArmKing's GitHub . Top Alternatives for Android