What is contributing to my project size?

One of my projects keeps using more and more space in our gitlab self-hosted instance. I have deleted all artifacts, cache, old pipelines and jobs. I am still seeing an usage of almost 9GB for a project whose repository is barely 100MB.

GitLab 12.7.5-ee (19edff260da)
GitLab Shell11.0.0
GitLab Workhorsev8.20.0
GitLab APIv4
GitLab Pages1.12.0
Ruby2.6.5p114
Rails5.2.3
PostgreSQL10.9

Storage: 8.6 GB (Repository: 90.3 MB / Wikis: 113 KB / Build Artifacts: 8.5 GB / LFS: 0 Bytes)

I know neither how these “Build Artifacts” are being created nor where are they stored, since they do not belong to any job (I have deleted those and their artifacts).

Thanks for taking the time to answer :slight_smile: