Json key words for setting Alt text values in a theme file

[SteveD]

Does anyone know the Json keywords and sequence for setting the Alt Text in a visual? My current keyword and sequence are;

"visualkeyword": {
"*": {
"altText":{
"Value": " some text here " }
}
)

which isn't doing anything. Any help would be appreciated.

[amitchandak]

@SteveD , refer if the few links given here can help. I doubt alt text

https://community.powerbi.com/t5/Community-Blog/Power-BI-Theme-Generators/ba-p/2265899

[SteveD]

Good resources but, nothing on Alt Text.