Button for hiding rows

[PP3321]

Dear Chandoo community,
Thank you always for your help...today I have one problem...
I came across a worksheet that has these buttons on the left.
Please see attached.

I do not know the name for this feature, so I could not google it.
Can anyone please tell me what this is...?

Thanking you in advance...

 

[Nebu]

Hi:

Its called grouping in excel.

Thanks

 

[PP3321]

@Nebu
thank you so much!