You have 2 options to customize panel.min.js / frontend.min.js files.
1) You can unminify it via one of the free online websites e.g. https://unminify.com/
2) You can use original Vue.js files. Here is more information about framework we use for dynamic parts of the website - https://vuejs.org/
Please download full package from your https://themeforest.net/downloads
Please unzip and you will find all vue files in the:
In 3 folders: