The interface required by OOF is shown in https://wiki.onap.org/pages/viewpage.action?pageId=40206714 . I use attachment to insert into db then GUI do rendering.
they have merged into engine/packages/base/src/files/install/mysql/data/

I find if there are two different layout field like type, the Policy GUI can’t fetch the layout, as follows:
FlavorFeatures:[
{
“id”:…
“type”:….
“directives”:[
“type”:….
“attributes”:[]
]

}
]

the GUI can't show type.