FAssetTypeActions_Base overrides IAssetTypeActions, and has this description:
/** A base class for all AssetTypeActions. Provides helper functions useful for many types. Deriving from this class is optional. */
Deriving from it is optional, but in 4.13, every asset derived from it directly or indirectly. In 4.14, the only one we see that doesn’t is FAssetTypeActions_SoundEffectPreset. With the exception of ::CanLocalize, it looks like it mirrors the functionality of Base precisely, including the more complicated AssetsActivated and PerformAssetDiff functions.
This caused a minor problem for us because we had added extra functionality to IAssetTypeActions and extended it to FAssetTypeActions_Base. We’ve decided to make the change locally to inherit FAssetTypeActions_SoundEffectPreset from FAssetTypeActions_Base rather than duplicate some of those other functions we added, but that could of course be risky if there are later updates to SoundEffectPreset that rely on it not inheriting from base.
This obviously isn’t high priority, but if there is a reason it doesn’t inherit, we’d like to know, and if there isn’t, then we’d prefer it if it were changed to do the inheritance.