xrdb:tldr:87a2f

This command is used to load X resources from a file into the X server's resource database. Here is an explanation of each part of the command:

• xrdb: It is the command-line utility used for managing the X server's resource database.
• -load: This option specifies that the following argument is the file from which the resources will be loaded.
• ${~--Xresources}: This is a parameter expansion syntax used in some shells (such as zsh) to expand the value of the Xresources variable. The ~ operator enables pathname expansion (also known as tilde expansion), and the -- is used to indicate the end of options, ensuring that subsequent arguments are treated as file names even if they start with a hyphen.

So, when the command is executed, it will load the resources from the file specified by the value of the Xresources variable into the X server's resource database. The actual file name will depend on the value assigned to Xresources.