Investigating
REST API GET /rest/asset/v1/landingPages.json undocumented parameters
GET /rest/asset/v1/landingPages.json
I found undocumented parameters.
| (empty) | Maximum number of channels to return. Max 200, default 20 | query | string | |
| (empty) | Integer offset for paging | query | string |
It seems it's official as same as similar API's.