Hi there,
The current method of handling attribute aliases is confusing and does not appear to work for all formats that support aliases. I have tried to use it to write to a geopackage (a format that does support aliases) and the alias is not written. Other people are also struggling to write to formats such as ArcGIS Online that support aliases.
I would like to suggest that you add a new column in all writer for formats that support aliases, where you can specify the alias value.
Aliases should also be read in on all readers for formats that support them and persist through transformations to the written output if the writer also supports them.
They should also be exposed and editable in transformers such as the attribute manager.
Regards,
Marc

