What does the triangle beside sd card in open from list mean

[Android Central Question]

When sending a document by WhatsApp, we open browse other documents and after that we slide from right hand there the list comes written open from and down there is written picture, audio, video, SD card. Beside SD card there comes a small triangle and under that triangle there is a line. What does that mean? What's the function of that button can anyone please tell.

 

[mustang7757]

Which phone, can you post a screenshot ?
https://forums.androidcentral.com/showthread.php?t=413366

I'll leave a link to register so you can communicate here, as a guest account u cant .
https://forums.androidcentral.com/showthread.php?t=409154

 

[Rukbat]

[Moved to WhatsApp forum for better exposure]