需要修改源码重新编译，编译步骤见：https://www.0z.gs/webDevelopment/856.html 文末

subconverter/src/server/webserver_httplib.cpp
148 行，注释掉

//   res.set_header("Server", "subconverter/" VERSION " cURL/" LIBCURL_VERSION);

subconverter/src/handler/webget.cpp
34 行，注释掉，另起一行

//static auto user_agent_str = "subconverter/" VERSION " cURL/" LIBCURL_VERSION;
static auto user_agent_str = "";

182-183 行，注释掉

// header_list = curl_slist_append(header_list, "SubConverter-Request: 1");
// header_list = curl_slist_append(header_list, "SubConverter-Version: " VERSION);

subconverter/src/server/webserver.h
54 行，注释掉，另起一行

// std::string user_agent_str = "subconverter/" VERSION " cURL/" LIBCURL_VERSION;
std::string user_agent_str = "";