An owner computer system (205, 305, 405, 500, 705, 805, 905, 1010, 1210) comprising: one or more processors; and one or more computer-readable hardware storage devices having stored thereon computer-executable instructions that are structured to be executable by the one or more processors to thereby cause the owner computer system to: within a debugging session (1005, 1100, 1200) in which the owner computer system and a participant computer system (210, 310, 410, 600, 710, 810, 910, 1205) are both members, provide access to a build instance of a multi-file workspace, the access being provided to the owner computer system and the participant computer system, wherein the multi-file workspace and the build instance are both stored locally on the owner computer system, the multi-file workspace includes multiple files of source code, and the build instance is a build of the source code, and wherein the owner computer system and the participant computer system share control of a single debug cursor signifying where a stop event has occurred in the executing source code and which portion of the source code will be executed next; receive a plurality of debug commands (1035, 1040, 1045) directed to the build instance, wherein some of the plurality of debug commands originate from the owner computer system and some of the plurality of debug commands originate from the participant computer system; multiplex the plurality of debug commands, wherein multiplexing includes organizing the plurality of debug commands into a determined order; and for each debug command of the multiplexed plurality of debug commands, in the determined order, execute the debug command against the build instance at a current location of the shared debug cursor in the source code only on the owner computer system to generate debugging data; and publish the debugging data to the owner computer system and to the participant computer system. one or more processors; and one or more computer-readable hardware storage devices having stored thereon computer-executable instructions that are structured to be executable by the one or more processors to thereby cause the owner computer system to: within a debugging session (1005, 1100, 1200) in which the owner computer system and a participant computer system (210, 310, 410, 600, 710, 810, 910, 1205) are both members, provide access to a build instance of a multi-file workspace, the access being provided to the owner computer system and the participant computer system, wherein the multi-file workspace and the build instance are both stored locally on the owner computer system, the multi-file workspace includes multiple files of source code, and the build instance is a build of the source code, and wherein the owner computer system and the participant computer system share control of a single debug cursor signifying where a stop event has occurred in the executing source code and which portion of the source code will be executed next; receive a plurality of debug commands (1035, 1040, 1045) directed to the build instance, wherein some of the plurality of debug commands originate from the owner computer system and some of the plurality of debug commands originate from the participant computer system; multiplex the plurality of debug commands, wherein multiplexing includes organizing the plurality of debug commands into a determined order; and for each debug command of the multiplexed plurality of debug commands, in the determined order, execute the debug command against the build instance at a current location of the shared debug cursor in the source code only on the owner computer system to generate debugging data; and publish the debugging data to the owner computer system and to the participant computer system. within a debugging session (1005, 1100, 1200) in which the owner computer system and a participant computer system (210, 310, 410, 600, 710, 810, 910, 1205) are both members, provide access to a build instance of a multi-file workspace, the access being provided to the owner computer system and the participant computer system, wherein the multi-file workspace and the build instance are both stored locally on the owner computer system, the multi-file workspace includes multiple files of source code, and the build instance is a build of the source code, and wherein the owner computer system and the participant computer system share control of a single debug cursor signifying where a stop event has occurred in the executing source code and which portion of the source code will be executed next; receive a plurality of debug commands (1035, 1040, 1045) directed to the build instance, wherein some of the plurality of debug commands originate from the owner computer system and some of the plurality of debug commands originate from the participant computer system; multiplex the plurality of debug commands, wherein multiplexing includes organizing the plurality of debug commands into a determined order; and for each debug command of the multiplexed plurality of debug commands, in the determined order, execute the debug command against the build instance at a current location of the shared debug cursor in the source code only on the owner computer system to generate debugging data; and publish the debugging data to the owner computer system and to the participant computer system. execute the debug command against the build instance at a current location of the shared debug cursor in the source code only on the owner computer system to generate debugging data; and publish the debugging data to the owner computer system and to the participant computer system.