This article will look at some of the opportunities you’ll have when you pull in your libraries inline rather than leaving them as references to external files, all without leaving the IDE
For the more advanced Google Apps Script developer this is a great article to get your teeth into which should also hopefully give you some tips to help manage and maintain complex Apps Script projects.
Source: Opportunities and workflows inlining Apps Script libraries – Desktop Liberation
Member of Google Developers Experts Program for Google Workspace (Google Apps Script) and interested in supporting Google Workspace Devs.