With the SQL view vSMSServiceWindow, there are a column Schedules. This column allows you to see exactly what day Maintenance Window is scheduled for. The correspond supported SQL view is vServiceWindow. However, that column isn’t listed without it being listed there is no way to determine what day an MW applies too.

Select distinct

isnull(SWin.Name,'No Maintenance Windows') as 'SWinName',

isnull(SWin.IsGMT,'') as 'SWinIsGMT',

SWin.StartTime as 'SWinStartTime',

isnull(SWin.Duration,0) as 'SWinDuration',

case 

    when isnull(SWin.ServiceWindowType, 0) = 0 then 'No Maintenance Windows'

    when SWin.ServiceWindowType=1 then 'All Programs Service Window'

    when SWin.ServiceWindowType=2 then 'Program Service Window'

    when SWin.ServiceWindowType=3 then 'Reboot Required Service Window'

    when SWin.ServiceWindowType=4 then 'Software Update Service Window'

    when SWin.ServiceWindowType=5 then 'OSD Service Window'

    when SWin.ServiceWindowType=6 then 'Corresponds to non-working hours'

    else 'unknonwn' 

end as 'SWinType' 

from

dbo.v_Collection Col

left outer join dbo.v_ServiceWindow SWin on Col.CollectionID = SWin.CollectionID

Below are the results of the query above.
All Friday 0 2019-01-09 00:00:00.000 1439 All Programs Service Window
All Monday 0 2019-01-09 00:00:00.000 1439 All Programs Service Window
All Saturday 0 2019-01-09 00:00:00.000 1439 All Programs Service Window
All the time except for Sunday between 00:00 - 04:00 0 2019-01-09 04:00:00.000 1199 All Programs Service Window
All Thursday 0 2019-01-09 00:00:00.000 1439 All Programs Service Window
All Tuesday 0 2019-01-09 00:00:00.000 1439 All Programs Service Window
All Wednesday 0 2019-01-09 00:00:00.000 1439 All Programs Service Window
Exactly what day does the 4 row happen on? Are you sure? There is no way to tell from the SQL view.

So why is this information important? Knowing the exact details of MW helps when troubleshooting. This also allows for a dashboards/reports to be created so that CM administrators can quickly look to see if there are any problems allowing them to quickly isolate what problems they might have or better yet eliminate that as the likely issue. This will also allow CM admin to meet and validate they are meeting this KPIs for deployments.

To ramp up, this view, even more, translate all of the schedule items to their respective values.

As soon as an SCCM update is installed, the clients for the previous version will be displayed in Asset Intelligence > Product Lifecycle as "nearing end-of-support in next 18 months". Each version of SCCM is only supported for 18 months anyway, meaning if you have 10000 clients then you immediately have a bar of 10000 installs nearing end of support which squashes any other products' bars on the chart - see attachment for an example. Obviously this is solved by updating the clients but this could be a months-long process in some environments so it renders the dashboard far less useful immediately following an upgrade.

I would like to suggest that the way this information is displayed is presented differently to avoid this, it's useful to have the end of support information for SCCM in the dashboard but perhaps for this product it could only be shown if end of support is less than 6 or 12 months away? Alternatively, an option to show or hide this product would be great.