What does the command "\newblock" in bibliographies do?

Question

I have been manually changing a bibstyle created with makebib to achieve a given look of the references. Since I ended up deleting a few new.block commands in the .bst-file and I realised that this removes the corresponding \newblock-command in the .bbl-file, I was wondering what LaTeX-command \newblock actually does.

I am using the article class at the moment but in general I am interested in whether deleting the new.block parts in the bst-file might cause spacing problems or other problems in some cases.

To be more precise, I do not see a difference between

\documentclass{article}

\begin{document}
  \begin{thebibliography}{1}
  \bibitem{Author2016Fancy}
    A. Author \newblock \emph{A Very Interesting Book}. Fancy Series, vol. 42,  \newblock Famous Publisher, 2016.
  \end{thebibliography}
\end{document}

and

\documentclass{article}

\begin{document}
  \begin{thebibliography}{1}
  \bibitem{Author2016Fancy}
    A. Author \newblock \emph{A Very Interesting Book}. Fancy Series, vol. 42, Famous Publisher, 2016.
  \end{thebibliography}
\end{document}

Answer 1

In the standard classes \newblock is defined as

\newcommand\newblock{\hskip .11em\@plus.33em\@minus.07em}

so it makes a horizontal space, if you use the [openbib] document class option then it is redefined to be \par so force a paragraph break between "blocks" of each entry,