Error on Mac (Catalina): brew prefix --openssl

I recently tried to install phpbrew to install PHP 5.6 on my MacBook (OSX Catalina).
But it failed with error message about openssl.
As I’ve discovered, openssl was replaced by libressl on Catalina.
I’ve created an issue on the phpbrew github, but they said that this should be handled by Homebrew, that Homebrew should provide the openssl for Mac Catalina (to install PHP 5.6)

volk ~ $ brew --prefix openssl

Error: openssl: /usr/local/Homebrew/Library/Taps/homebrew/homebrew-core/Aliases/openssl:1: syntax error, unexpected ..

../Formula/openssl@1.1.rb

^~

/usr/local/Homebrew/Library/Taps/homebrew/homebrew-core/Aliases/openssl:1: unknown regexp options - pl

/usr/local/Homebrew/Library/Taps/homebrew/homebrew-core/Aliases/openssl:1: `@1' is not allowed as an instance variable name

I doubt you’d be able to compile php 5.6 with openssl 1.1 since that didn’t exist yet when 5.6 was released. Can you try this command again after a brew update?

volk ~ $ brew --version
Homebrew 2.2.2
Homebrew/homebrew-core (git revision c377; last commit 2019-12-30)
volk ~ $ brew update
Updated 1 tap (homebrew/core).
==> New Formulae
bandwhich                               cgns                                    komposition                             mlpack                                  poetry                                  yaegi
==> Updated Formulae
freetds ✔                     deno                          git-remote-hg                 leptonica                     ndpi                          pandoc                        re2                           typescript
python ✔                      diff-pdf                      glassfish                     lerna                         nethack                       passwdqc                      run                           uhd
aliyun-cli                    django-completion             glfw                          libarchive                    ngspice                       pcsc-lite                     securefs                      ultralist
apache-geode                  doitlive                      glooctl                       libngspice                    nift                          pdftoipe                      serverless                    vim
appium                        doxygen                       gnuradio                      librealsense                  node-build                    peco                          singular                      vips
aptly                         dvc                           google-authenticator-libpam   libsixel                      now-cli                       perl                          siril                         visp
arduino-cli                   easyengine                    gr-osmosdr                    liquibase                     ntl                           phpstan                       smartmontools                 volatility
ask-cli                       elvish                        grep                          maxwell                       ntopng                        picard-tools                  socat                         wal2json
awscli                        embree                        help2man                      mdds                          onefetch                      pipx                          sourcekitten                  watch
ballerina                     exploitdb                     hugo                          midnight-commander            ooniprobe                     poppler                       sqlmap                        weechat
caffe                         eye-d3                        ilmbase                       minimal-racket                opa                           pre-commit                    subversion                    whois
certbot                       ffmpeg                        imagemagick                   minio                         opencv                        primesieve                    swiftformat                   wxmaxima
chakra                        field3d                       imagemagick@6                 minio-mc                      opencv@2                      proj                          swiftlint                     xmrig
citus                         flow                          jdupes                        mitmproxy                     opencv@3                      pwntools                      synfig                        yamllint
click                         frpc                          jenkins                       molecule                      openexr                       pyenv                         taskell                       you-get
coffeescript                  frps                          jfrog-cli-go                  mpd                           openimageio                   python-yq                     terrahub                      youtube-dl
cointop                       ghq                           jpeg-turbo                    msmtp                         opensc                        ranger                        tmuxinator
ctl                           git-annex                     k3d                           nano                          openvdb                       rav1e                         toast
ctop                          git-lfs                       ldc                           ncompress                     paket                         rawtoaces                     tunnel
==> Deleted Formulae
diffuse           hg-flow           ipython@5         mysql-utilities   node@8            pygobject         pygtk             pygtkglext        pygtksourceview   redo              terminator        vte               zim
volk ~ $ brew --version
Homebrew 2.2.2
Homebrew/homebrew-core (git revision 2ed5f; last commit 2020-01-06)
volk ~ $ brew --prefix openssl
Error: openssl: /usr/local/Homebrew/Library/Taps/homebrew/homebrew-core/Aliases/openssl:1: syntax error, unexpected ..
../Formula/openssl@1.1.rb
^~
/usr/local/Homebrew/Library/Taps/homebrew/homebrew-core/Aliases/openssl:1: unknown regexp options - pl
/usr/local/Homebrew/Library/Taps/homebrew/homebrew-core/Aliases/openssl:1: `@1' is not allowed as an instance variable name

what does ls -al /usr/local/Homebrew/Library/Taps/homebrew/homebrew-core/Aliases/openssl show?