The usermod command is a utility for modifying user accounts. One of its options is -G, which allows specifying a list of supplementary groups that the user is a member of. If the user is currently a member of a group that is not listed, the user will be removed from that group. For example, to remove the user alice from the group sales, one can use the command sudo usermod -G admin alice, assuming that alice is only a member of admin and sales groups. Alternatively, one can use the gpasswd command with the --delete option to remove a user from a specific group without affecting other groups. For example, to remove the user alice from the group sales, one can use the command sudo gpasswd --delete alice sales. The other commands in the options are not used for removing a user from a group. The grouprm command does not exist. The groupmod command is used for modifying group attributes, not membership. The passwd command is used for changing user passwords, not groups. The usergroups command is used for displaying the groups that a user belongs to, not modifying them. Reference:
usermod(8) - Linux man page
gpasswd(1) - Linux man page
How to Remove User From Group in Linux [Quick Tip]

/usr/bin/xwininfo, xwininfo
Explanation:
The command that can be used to investigate the properties for a particular window in X by clicking that window is xwininfo. xwininfo is a command-line tool that provides information about X windows. When executed, it opens a small window and waits for the user to select a window by clicking on it. Then, it displays various characteristics about the window in question, such as its geometry, position, size, depth, class, name, id, and more. xwininfo is part of the X Window System, which is a graphical user interface system for Unix-like operating systems. xwininfo can be useful for debugging, testing, or scripting purposes. References:
https://bing.com/search?q=command+to+investigate+properties+of+a+window+in+X
https://www.exam-answer.com/linux-foundation-certified-system-administrator-lfcs-simulation-investigate-wind