What is Flux constructed with?

Flux is a tool for keeping Kubernetes clusters in sync with sources of configuration (like Git repositories) and automating updates. The modern version of Flux (v2 and later) is constructed with a set of composable APIs and controllers known as the GitOps Toolkit. This toolkit provides specialized components for source management (Source Controller), Kustomize builds (Kustomize Controller), Helm releases (Helm Controller), and notifications (Notification Controller), which together form the foundation of Flux's functionality.

A. GitLab Environment Toolkit is a collection of tools for managing GitLab instances, not the foundational components of Flux.
C. While the GitOps Toolkit includes a Helm Controller, Flux itself is not constructed with a "Helm Toolkit"; this is just one component of the larger toolkit.
D. GitHub Actions Toolkit is a set of Node.js packages for creating GitHub Actions, which is unrelated to the core architecture of Flux.

1. FluxCD Documentation. (n.d.). Flux. Retrieved from https://fluxcd.io/. (The homepage states: "Flux is a tool for keeping Kubernetes clusters in sync with sources of configuration... It is constructed with the GitOps Toolkit...")

2. FluxCD Documentation. (n.d.). The GitOps Toolkit. Retrieved from https://fluxcd.io/flux/components/. (This page details the components of the GitOps Toolkit, describing it as the foundation of Flux.)

3. Cloud Native Computing Foundation. (n.d.). Flux. CNCF Projects. Retrieved from https://www.cncf.io/projects/flux/. (The project description confirms Flux is built on the GitOps Toolkit.)