@Laurent Knafo Thank you for reaching out to Microsoft Q&A. Apologize for the inconvenience caused any on this.
/ss-oryx/app
path is where the files will be during the pipeline run temporarily before they get published them to SWA.
I have checked with internal product team on this and sharing their response below
In static webapps you cannot find the output files of the build and all the output files generated will be managed by the platform only as per the By-design
Feel free to reach back to me if you have any questions on this.