Name of the spare part for xperia z5 6653, need help for repairing

[anttihhh85]

Hello, I have a xperia z5 6653 which had screen shattered some time ago, there's no warranty anymore so I tried to assemble new screen. It went well but one part broke (some sort of black rail about a little longer than battery itself? in right side of the battery place) and I need to find somewhere corresponding spare part and start the project again. There is no picture because I throw it to carbage can already but enclosed is picture from internet where it can be seen, I marked that part in circle and arrow. Hopefully I get some help, thanks.

[Uliwooly]

@anttihh85

https://www.ifixit.com/Guide/Sony+Xperia+Z5+LCD+Screen+Replacement/52649

Isn't that the motheraboard? 

Did you had another account?

[anttihhh85]

Hello,

No I don't have anpther account, sorry. I just use this account to try to solve this.

No, the part is not the motherboard, in the picture no. 10 in the link you sent there is a black some sort of protective rail\list below that motherboard part  (back of the phone, right side of the battery, below the right side motherboard). It must be replaceable part because it sprang out from there but accidentally when I tried to insert it back below the motherboard, it broke to two pieces because that list is very thin.