A **custom build** is a build that is using most of the /e/ source code to generate a new ROM. It can be modified in any manner by the developer, for any purpose.
The Heimdall project does not provide package for the last version. So you need to build it manually from [our fork](https://gitlab.e.foundation/e/tools/heimdall). Bellow the documentation for each platform, extracted from README of Heimdall project.