Error: from config: failed to resolve output format "WebAppManifest" from site config

[EloiMartinet]

Hello,
I installed wowchemy and deployed it on Netlify a few month ago (maybe July). I didn't re-used it since.
I tried to launch the command hugo server but i get the error
Error: from config: failed to resolve output format "WebAppManifest" from site config
I tried to delete hugo's cache as said in https://wowchemy.com/docs/hugo-tutorials/troubleshooting/#error-failed-to-resolve-output-format, or what is described at #2800 but it didn't work. If it is a missing module, I don't know which one. Could you help me with it ?
My hugo version is
Hugo Static Site Generator v0.68.3/extended linux/amd64 BuildDate: 2020-03-25T06:15:45Z
Here is the repo : https://gitlab.com/EloiM/starter-hugo-academic

Thank you all.
Best,
Eloi.

[gcushen]

Have you tried temporarily removing the WebAppManifest from your site config?

Also, you're unlikely to find much support without sharing your GitHub repository (at the same state that you experience the issue) so that the community can attempt to reproduce your issue and help you?

What does "I tried to update it using hugo" mean? What commands or changes did you make? What version of Hugo are you now using?

[EloiMartinet]

I tried to remove WebAppManifest from the config but it didn't work.
Sorry for the repo and informations, I added it in the original post.