\documentclass[
twoside,
% parskip=half,
english,
headings=small,
headinclude,
]{scrreprt}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{babel}
\usepackage{libertine}
\usepackage{graphicx}
\usepackage[automark]{scrlayer-scrpage}
\usepackage[style=authoryear,maxcitenames=3,backend=biber]{biblatex}
\addbibresource{mainbib.bib}
\usepackage{blindtext}% gives the filler text at the very end.
\usepackage{hyperref}% hyperlinks in this sample bibliography
\hypersetup{pdfborder = 0 0 .5}