The edit tool allows the owner of the topic to modify it, copy it, delete it and create new topics. The Web is highly flexible in its handling of different types of data. Any new type of data can be handled provided the server can be configured to recognise it and the client can be configured to do something with it. Most servers recognise data types of files by the filename extension. The file is then tagged with a code to identify its type before being sent to the client.
Clients store a list of codes with instructions on what to do with data tagged with each code.
Usually the instructions indicate an application to run to display or process the particular sort of data.