When messages are process and tagged by Retention Policy.The tag information along with the expiry date can be viewed in Outlook and OWA.
There are some minor differences in the way this information is displayed in Outlook and OWA.
For example,if we have a tag for Inbox ,depending upon the number of days the message is going to be expired,the tag information on a message would change a bit.
If the number of days remaining for the message to expire is more than 30 days,tag information on the message will be display as below ;
above we see information like the name of the tag and the date when the message is going to expire.
But when the number of days remaining for the message to expire is less than 30 days,we would see additional retention information on the message.
above we see additional information like the number of days remaining for the message to expire.
Hope this helps !