[Health-dev] Some xml related questions

[Kaushik S]

Hello,
    Looking at the hello world xml, I would like to know what the following keywords mean -

1. sequence  (Eg <menuitem name="Hello World" id="menu_hello_world" sequence="10" />  )

2. eval   (In act_window.view,   <field name="sequence" eval="10"/>   )

3. res_model (In action.act_window <field name="res_model">hello.hello</field> )
what is res_model. This seems the same as model? whats the difference?

4. If I change my module's xml, should I restart the client?  My xml is in the directory of the module's init.py (not inside a view directory). I restart the server with -u option.

If I missed it in  online  documentation apologies.

Thanks
Kaushik