@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.
{
    for (size_t i = 1; i < split.size(); ++i) {
        Span<const char> elem = split[i];
        bool hardened = false;
        if (elem.size() > 0) {
            const char last = elem[elem.size() - 1];
            if (last == '\'' || last == 'h') {
                elem = elem.first(elem.size() - 1);
                hardened = true;
                apostrophe = last == '\'';
            }
        }
        uint32_t p;
        if (!ParseUInt32(std::string(elem.begin(), elem.end()), &p)) {
            error = strprintf("Key path value '%s' is not a valid uint32", std::string(elem.begin(), elem.end()));
            return false;
        } else if (p > 0x7FFFFFFFUL) {
            error = strprintf("Key path value %u is out of range", p);
            return false;
        }
        out.push_back(p | (((uint32_t)hardened) << 31));
    }
    return true;
}
std::unique_ptr<PubkeyProvider> ParsePubkeyInner(uint32_t key_exp_index, const Span<const char>& sp, ParseScriptContext ctx, FlatSigningProvider& out, bool& apostrophe, std::string& error)