After review with Martin, here following point to fix:

• under Administration > Plugins > Webservice: add an overview page explaining how to set access with token

• users as client with token
• one system controlling moodle (eg student information system) with token
  For each step indicate if the setting is enable or not.

• on Token profil page:

• change the title name - web service token => web service management
• always display automatically generated tokens with a Reset button for each service
• if admin created some tokens, display these tokens without reset button.

• on admin manage protocol page:

• remove "the table above are sorted automatically"
• change text: For security reason only protocol that are in used should be enabled

• on admin manage token page:

• when https disabled, display the string as ******************
• change text: No token have been created

*on admin manage service pages

• move add link to the left under the table
• top navigation should be consistent (check other page too) - no need back button on the function selection page
• make the search selector multiple => can select multiple function
• change buttons labels "Saves changes" => "add function", ...
• add help information to the required capability field
• add help text to indicate that a service is made of function
• the Add function button is weird (css?)
• remove the "Save changes" button on the manage service page

• change exception "invalid token" in a more explicit message (not valid, IP restriction,...)