sudo apt install kwin-style-qtcurve
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages were automatically installed and are no longer required:
  aptdaemon diffstat gettext hardening-includes intltool-debian
  kde-config-pimactivity libapt-pkg-perl libarchive-zip-perl libasprintf-dev
  libautodie-perl libclass-accessor-perl libclone-perl libcroco3 libdpkg-perl
  libemail-valid-perl libfile-fcntllock-perl libgettextpo-dev libgettextpo0
  libio-pty-perl libio-string-perl libipc-run-perl libipc-system-simple-perl
  libkwineffects1abi4 liblist-moreutils-perl libnepomukcleaner4
  libnet-dns-perl libnet-domain-tld-perl libnet-ip-perl libokularcore4
  libparse-debianchangelog-perl libperlio-gzip-perl libpimactivity4
  libsub-identify-perl libsub-name-perl libtext-levenshtein-perl libunistring0
  lintian mysql-server-core-5.5 nepomuk-core-runtime patchutils
  python3-aptdaemon python3-defer shared-desktop-ontologies t1utils
Use 'apt-get autoremove' to remove them.
The following extra packages will be installed:
  kde-style-qtcurve
Suggested packages:
  gtk2-engines-qtcurve
The following NEW packages will be installed:
  kde-style-qtcurve kwin-style-qtcurve
0 upgraded, 2 newly installed, 0 to remove and 0 not upgraded.
Need to get 402 kB of archives.
After this operation, 1,487 kB of additional disk space will be used.