A build server is a distinct concept to a Continuous Integration (CI) server. The CI server exists to build your projects when changes are made. By contrast a Build server exists to build the project (typically a release, against a tagged revision) on a clean environment. It ensures that no developer hacks, tweaks, unapproved config/artifact versions or uncommitted code makes it into the released code.
Checkmarx Launches Infrastructure as Code Scanning Solution to Secure Cloud-Native Applications: KICS