I recall that Hugo will throw an error if output is invalid, which is useful for checking if the config is correct on the user side, such as errors caused by typos or forgetting to import modules.
For example.
// hugo.toml
outputs:
home:
- HTML
- ABC
The ABC wasn’t defined anywhere.
With 113:
~/Downloads/hugo113 version && ~/Downloads/hugo113
hugo v0.113.0-085c1b3d614e23d218ebf9daad909deaa2390c9a+extended linux/amd64 BuildDate=2023-06-05T15:04:51Z VendorInfo=gohugoio
Total in 11 ms
Error: failed to create config from modules config: unknown output format "abc" for kind "home"
With 128, 137, 140.1:
~/Downloads/hugo128
Start building sites …
hugo v0.128.1-0ff542b4b9cc7b5cb425bbab8bdb5aace81d0c03+extended linux/amd64 BuildDate=2024-07-02T06:46:41Z VendorInfo=gohugoio
WARN found no layout file for "html" for kind "taxonomy": You should create a template file which matches Hugo Layouts Lookup Rules for this combination.
| EN
-------------------+-----
Pages | 5
Paginator pages | 0
Non-page files | 0
Static files | 0
Processed images | 0
Aliases | 0
Cleaned | 0
Total in 14 ms