Manifest files are similar in nature to declaration files in that both specify the expected structure of a computer program to be consumed by another computer program, providing additional information that allow system software, software-defined tools (e.g., compilers, linters), development environments, or other developers to understand how to interact with certain resources or code.
For instance, manifest files describe things like dependencies, permissions, or runtime settings that control the execution of code.
The primary purpose is to enumerate the files which are included in the distribution, either for processing by various packaging tools or for human consumption.
Manifests may contain additional information; for example, in JAR (a package format for delivering software written in Java programming language), they can specify a version number and an entry point for execution.
A cache manifest in HTML5 is a plain text file accompanying a web app that helps it run when there is no network connectivity.
[4] Example of a cache manifest: A webmanifest is a JSON file used in progressive web apps to make them easily shareable via a URL, discoverable by a search engines, and alleviates complex installation procedures.