@achow101 noted we don't reject them therefore they must be silently accepted. This is not part of the specs, we should remove them. Also cc @sipa.

I can take care of this.
size_t GetSize() const override { return m_provider->GetSize(); }
    std::string ToString(StringType type) const override { return "[" + OriginString(type) + "]" + m_provider->ToString(type); }
    bool ToPrivateString(const SigningProvider& arg, std::string& ret) const override
    {
        std::string sub;
        if (!m_provider->ToPrivateString(arg, sub)) return false;
        ret = "[" + OriginString(StringType::PUBLIC) + "]" + std::move(sub);
        return true;
    }
    bool ToNormalizedString(const SigningProvider& arg, std::string& ret, const DescriptorCache* cache) const override
    {
        std::string sub;
        if (!m_provider->ToNormalizedString(arg, sub, cache)) return false;
        
        
        
        if (sub[0] == '[') {
            sub = sub.substr(9);
            ret = "[" + OriginString(StringType::PUBLIC, true) + std::move(sub);
        } else {
            ret = "[" + OriginString(StringType::PUBLIC, true) + "]" + std::move(sub);
        }
        return true;
    }
    bool GetPrivKey(int pos, const SigningProvider& arg, CKey& key) const override
    {
        return m_provider->GetPrivKey(pos, arg, key);
    }
};
class ConstPubkeyProvider final : public PubkeyProvider