At the installation of a phpBB board, a specific forum role is created for bots.

Bot Access

• Can see forum
• Can see topics
• Can read forum
• Can print topics
• Can download files

The two last permissions are problematic.

Can print topics : links to print topics are hidden due to a template file (condition not S_IS_BOT in viewtopic_topic_tools.html). Moreover, there is a meta tag with robots as name and noindex as content in viewtopic_print.html. Therefore, it doesn't make sense to enable the print topics permission to bot. It's even misleading, as an administrator may believe that it's accessible to bots by testing their permissions.

Can download files : this permission is even more problematic and that's why I set the priority of this issue as major instead of minor. The problem is that permission isn't actually enabled due to the user permissions assigned to the group. In fact, all user permissions are set at "No" for bots, including "Can download files". That user permission overrides the forum one. As a result, no (image) attachment can be indexed by Google or other identified search engines if the administrator doesn't fix the inconsistent bot permissions.

The fix should be simple for future boards.

In install\schemas\schema_data.sql, two user permissions are set for guests

# GUESTS - u_download and u_search ability

INSERT INTO phpbb_acl_groups (group_id, forum_id, auth_option_id, auth_role_id, auth_setting) SELECT 1, 0, auth_option_id, 0, 1 FROM phpbb_acl_options WHERE auth_option IN ('u_', 'u_download', 'u_search'); 

u_download should be enabled for bots.

For existing boards, a fix could be added too.