Google has completed the rollout of brand guidelines for all Performance Max campaigns created via the Google Ads UI. API-based campaigns will follow soon.
Brand assets like business name and logo now exist at the campaign level rather than the asset group level. This update enhances brand consistency and centralizes asset control.

API users must update their implementation: brand guidelines are now accessed via CampaignAsset, not AssetGroupAsset. Use the Campaign.brand_guidelines_enabled field to detect or configure this setting.
Starting with API v21, brand guidelines will be enabled by default for all new PMax campaigns. Migration for existing campaigns will finish by October 30, 2025.
Read here for more details: What you need to know about the business name and logo asset migration in PMax Campaigns.