How to list variables declared in script in sh (dash)?

I have seen How to list variables declared in script in bash? - but it does not help me in this case.

I would like to dump all environment and shell variables that Android Studio 4.0.1 sees on Ubuntu 18.04. The startup script is ./android-studio/bin/studio.sh, and the header is:

$ head -1 ./android-studio/bin/studio.sh
#!/bin/sh

So, it is a sh script (not bash), which in Ubuntu 18.04 is dash:

$ ls -la /bin/sh
lrwxrwxrwx 1 root root 4 Oct  4  2018 /bin/sh -> dash

So, basically, inside the code I can intervene here:

...
CLASSPATH="$CLASSPATH:$IDE_HOME/lib/jna.jar"
CLASSPATH="$CLASSPATH:$JDK/lib/tools.jar"
if [ -n "$STUDIO_CLASSPATH" ]; then
  CLASSPATH="$CLASSPATH:$STUDIO_CLASSPATH"
fi

# dump env - debug
env

# ---------------------------------------------------------------------
# Run the IDE.
# ---------------------------------------------------------------------
IFS="$(printf '\n\t')"
...

So, you can see there is a CLASSPATH variable there, I would like to dump it to stdout. However, just env will not print it - when I run this script, I get:

$ ./android-studio/bin/studio.sh
LESSOPEN=| /usr/bin/lesspipe %s
USER=myuser
LANGUAGE=en_US:en
TEXTDOMAIN=im-config
XDG_SEAT=seat0
SSH_AGENT_PID=1968
XDG_SESSION_TYPE=x11
SHLVL=2
QT4_IM_MODULE=xim
HOME=/home/myuser
OLDPWD=/path/to/android/android-studio/bin
DESKTOP_SESSION=ubuntu
GNOME_SHELL_SESSION_MODE=ubuntu
GTK_MODULES=appmenu-gtk-module:gail:atk-bridge:appmenu-gtk-module:appmenu-gtk-module:appmenu-gtk-module
PS1=\[\033[0;33m\]\u@TMPHIST:\W$\[\033[0;37;1m\] 
DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus
COLORTERM=truecolor
NVM_DIR=/home/myuser/.nvm
UBUNTU_MENUPROXY=1
MANDATORY_PATH=/usr/share/gconf/ubuntu.mandatory.path
IM_CONFIG_PHASE=2
LOGNAME=myuser
GTK_IM_MODULE=ibus
_=./android-studio/bin/studio.sh
DEFAULTS_PATH=/usr/share/gconf/ubuntu.default.path
USERNAME=myuser
XDG_SESSION_ID=975
TERM=xterm-256color
GNOME_DESKTOP_SESSION_ID=this-is-deprecated
WINDOWPATH=2
PATH=/home/myuser/.cargo/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/home/myuser/go/bin
SESSION_MANAGER=local/HPProBook430G4:@/tmp/.ICE-unix/29005,unix/HPProBook430G4:/tmp/.ICE-unix/29005
XDG_MENU_PREFIX=gnome-
S_COLORS=auto
GNOME_TERMINAL_SCREEN=/org/gnome/Terminal/screen/a30d7231_9e1a_47aa_8072_4b4ded3aeded
XDG_RUNTIME_DIR=/run/user/1000
DISPLAY=:0
LANG=en_US.UTF-8
XDG_CURRENT_DESKTOP=ubuntu:GNOME
LS_COLORS=rs=0:di=01;34:ln=01;36:mh=00:pi=40;33:so=01;35:do=01;35:bd=40;33;01:cd=40;33;01:or=40;31;01:mi=00:su=37;41:sg=30;43:ca=30;41:tw=30;42:ow=34;42:st=37;44:ex=01;32:*.tar=01;31:*.tgz=01;31:*.arc=01;31:*.arj=01;31:*.taz=01;31:*.lha=01;31:*.lz4=01;31:*.lzh=01;31:*.lzma=01;31:*.tlz=01;31:*.txz=01;31:*.tzo=01;31:*.t7z=01;31:*.zip=01;31:*.z=01;31:*.Z=01;31:*.dz=01;31:*.gz=01;31:*.lrz=01;31:*.lz=01;31:*.lzo=01;31:*.xz=01;31:*.zst=01;31:*.tzst=01;31:*.bz2=01;31:*.bz=01;31:*.tbz=01;31:*.tbz2=01;31:*.tz=01;31:*.deb=01;31:*.rpm=01;31:*.jar=01;31:*.war=01;31:*.ear=01;31:*.sar=01;31:*.rar=01;31:*.alz=01;31:*.ace=01;31:*.zoo=01;31:*.cpio=01;31:*.7z=01;31:*.rz=01;31:*.cab=01;31:*.wim=01;31:*.swm=01;31:*.dwm=01;31:*.esd=01;31:*.jpg=01;35:*.jpeg=01;35:*.mjpg=01;35:*.mjpeg=01;35:*.gif=01;35:*.bmp=01;35:*.pbm=01;35:*.pgm=01;35:*.ppm=01;35:*.tga=01;35:*.xbm=01;35:*.xpm=01;35:*.tif=01;35:*.tiff=01;35:*.png=01;35:*.svg=01;35:*.svgz=01;35:*.mng=01;35:*.pcx=01;35:*.mov=01;35:*.mpg=01;35:*.mpeg=01;35:*.m2v=01;35:*.mkv=01;35:*.webm=01;35:*.ogm=01;35:*.mp4=01;35:*.m4v=01;35:*.mp4v=01;35:*.vob=01;35:*.qt=01;35:*.nuv=01;35:*.wmv=01;35:*.asf=01;35:*.rm=01;35:*.rmvb=01;35:*.flc=01;35:*.avi=01;35:*.fli=01;35:*.flv=01;35:*.gl=01;35:*.dl=01;35:*.xcf=01;35:*.xwd=01;35:*.yuv=01;35:*.cgm=01;35:*.emf=01;35:*.ogv=01;35:*.ogx=01;35:*.aac=00;36:*.au=00;36:*.flac=00;36:*.m4a=00;36:*.mid=00;36:*.midi=00;36:*.mka=00;36:*.mp3=00;36:*.mpc=00;36:*.ogg=00;36:*.ra=00;36:*.wav=00;36:*.oga=00;36:*.opus=00;36:*.spx=00;36:*.xspf=00;36:
XDG_SESSION_DESKTOP=ubuntu
XMODIFIERS=@im=ibus
GNOME_TERMINAL_SERVICE=:1.975
XAUTHORITY=/run/user/1000/gdm/Xauthority
SSH_AUTH_SOCK=/run/user/1000/keyring/ssh
GOPATH=/home/myuser/go
CLUTTER_PAINT=continuous-redraw
SHELL=/bin/bash
QT_ACCESSIBILITY=1
GDMSESSION=ubuntu
LESSCLOSE=/usr/bin/lesspipe %s %s
TEXTDOMAINDIR=/usr/share/locale/
GPG_AGENT_INFO=/run/user/1000/gnupg/S.gpg-agent:0:1
XDG_VTNR=2
QT_IM_MODULE=ibus
PWD=/path/to/android
CLUTTER_IM_MODULE=xim
XDG_DATA_DIRS=/usr/share/ubuntu:/home/myuser/.local/share/flatpak/exports/share:/var/lib/flatpak/exports/share:/usr/local/share/:/usr/share/:/var/lib/snapd/desktop
XDG_CONFIG_DIRS=/etc/xdg/xdg-ubuntu:/etc/xdg
VTE_VERSION=5202
2020-09-07 06:00:33,977 [   1646]   WARN - com.intellij.ide.ui.LafManager - List.rowHeight = 0 in IntelliJ; it may lead to performance degradation 
...

Nope, no CLASSPATH variable dumped here.

So, how do I dump all environment and shell variables from sh (dash) script?