The dimensions are in the name of the STL-File:
L-Bracket1_Length_Width_Diameter_Thickness
Example: L-Bracket1_L20_W10_D5_T2
Diameter 5-5 = 5.5 (to avoid . in the file name).
If you can't find the right bracket for you, let me know.
The author marked this model as their own original creation.