ASTs, or Abstract Syntax Trees, are tree representations of code that power various development tools and can be useful for developers. They consist of a hierarchical structure where every node has at least a type specifying what it represents. ASTs are used in compilers, but also in tools like ESLint, Babel, and Prettier. Reading and traversing ASTs is common, especially for linting, while modifying and transforming ASTs can be done to perform tasks such as code optimization, bundling, and test coverage analysis. Printing ASTs can be used for formatting code according to a configuration or building custom minification tools. The use of ASTs in various projects and their benefits make them a valuable tool for developers to have in their toolbelt.