The automatic "insider" tag under your name shows you are either a Windows of Office "insider". At some point you click on a link (actually probably more than one link) to join the "insider" program. Unfortunately the tag does not identify if we are Windows
or Office insiders (hint hint moderators/owners). We can assume for now that you are an Office insider.
Being an insider simple means that you have volunteered to be an unpaid "crash test dummy" for MS. As an insider you have told MS that you are willing to let them send you program code they think is ready to be distribute to the general public. Buy sending
this code to insiders outside of MS they get to test in the real world on a wide variety of environments that even MS could not afford to setup and staff.
Being an insider has 2 issues. First, you have to invest time to keep up to date on what is new in each release. Second is that you may be luck enough to find a problem in the code, at best the feature just doesn't work, worst case it causes the program
to abend. Abends are a real problem if the corrupt your files, cause you to lose work and possibly prevent you from finishing important work. This is an aspect of being an insider that the "average" volunteer simply does not understand or appreciate fully.
2015 12 03- Inside being an Office Insider
http://new.office-watch.com/2015/inside-being-an-office-insider/