Stewards and Checkusers sometimes need to decide whether a case warrants a check or not. For example, sometimes the user might just be new and unaware of the policies instead of being a deliberate sockpuppet. This can be judged by getting an overall picture of a user's accounts, contributions and some other information. We want to surface this information via a 'Preliminary check' tab in Special:CheckUser 2.0. The information on this tab should be the similar to what is present on [Special:CentralAuth](https://meta.wikimedia.org/wiki/Special:CentralAuth?target=NKohli+%28WMF%29).
The preliminary check tab will only display public information and there is probably a future where this aggregated information will be integrated with Special:CentralAuth or there will be a way for non-CUs to access this. Because it is all public information, there will be nothing displayed if an IP address or a range is entered as in that case it would mean we tell the user about the users that have edited from those IPs. We could rethink this based on feedback. For the purposes of this ticket, the preliminary check only works for usernames.
=== Acceptance criteria
* There is a preliminary check tab underneath the input form
* Under the tab, there is a table with the headers:
*** Usernames supplied in the input form
** **Registration date**
*** Date-time on which the account was attached on the local wiki. This date is represented by the "Attached on" column in [Special:CentralAuth](https://meta.wikimedia.org/wiki/Special:CentralAuth?target=NKohli+%28WMF%29)
*** Local wiki their account is attached on. Wiki name in canonical form like - en.wikipedia.org, commons.wikimedia.org etc.
*** **Note** - There should be a 'home' icon next to their home wiki on the list. [Special:CentralAuth](https://meta.wikimedia.org/wiki/Special:CentralAuth?target=MarcoAurelio) denotes it in the //Method// column. For this user, meta wiki is their home wiki.
*** Number of edits on that wiki which links to the contributions page on that wiki
** **Block status**
*** Block status for the user with a link to the relevant block log (if possible)
** **User groups**
*** This one is not in the mocks already - it displays any groups that the user is a part of on that wiki like admin, sysop etc displayed in a comma-separated fashion.
* For each of the users entered in the input form, display all of the above information (following the mock structure)
* There is a link to the [Global contributions](https://tools.wmflabs.org/guc/) tool for each user under their username
* **Highlighting (!!This is still a WIP!!)**:
** We want to highlight rows with similar fields when the user hovers (or have a way to sticky-highlight) over a cell in a row that is similar to another row's cell value. For this tab, the highlight would work for:
*** Date (note that the registration date is a **date-time** field but the highlight should work for the same dates - discarding the time value)
** Good to note that highlighting would also work for the compare tab, over fields like the date, IP, UA etc.