The BLAS matrix product is not listed in the sessionInfo() output if run in RStudio from an R script or the console pane, but it is listed if run in an R session in the terminal/command line. It is also listed if rendered by rmarkdown or reprex.
From the RStudio R script pane or console pane.
sessionInfo()
#> R version 4.2.3 (2023-03-15)
#> Platform: aarch64-apple-darwin20 (64-bit)
#> Running under: macOS Ventura 13.3.1
#>
#> Matrix products: default
#> LAPACK: /Library/Frameworks/R.framework/Versions/4.2-arm64/Resources/lib/libRlapack.dylib
#>
#> locale:
#> [1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
#>
#> attached base packages:
#> [1] stats graphics grDevices utils datasets methods
#> [7] base
#>
#> loaded via a namespace (and not attached):
#> [1] rstudioapi_0.14 knitr_1.42 magrittr_2.0.3 R6_2.5.1
#> [5] rlang_1.1.0 fastmap_1.1.1 fansi_1.0.4 tools_4.2.3
#> [9] xfun_0.38 utf8_1.2.3 cli_3.6.1 clipr_0.8.0
#> [13] withr_2.5.0 htmltools_0.5.5 yaml_2.3.7 digest_0.6.31
#> [17] tibble_3.2.1 lifecycle_1.0.3 processx_3.8.1 callr_3.7.3
#> [21] vctrs_0.6.1 fs_1.6.1 ps_1.7.5 glue_1.6.2
#> [25] evaluate_0.20 rmarkdown_2.21 reprex_2.0.2 compiler_4.2.3
#> [29] pillar_1.9.0 pkgconfig_2.0.3
From an R session in the terminal/command line.
sessionInfo()
#> R version 4.2.3 (2023-03-15)
#> Platform: aarch64-apple-darwin20 (64-bit)
#> Running under: macOS Ventura 13.3.1
#>
#> Matrix products: default
#> BLAS: /Library/Frameworks/R.framework/Versions/4.2-arm64/Resources/lib/libRblas.0.dylib
#> LAPACK: /Library/Frameworks/R.framework/Versions/4.2-arm64/Resources/lib/libRlapack.dylib
#>
#> locale:
#> [1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
#>
#> attached base packages:
#> [1] stats graphics grDevices utils datasets methods base
#>
#> loaded via a namespace (and not attached):
#> [1] compiler_4.2.3 fastmap_1.1.1 cli_3.6.1 tools_4.2.3
#> [5] htmltools_0.5.5 withr_2.5.0 fs_1.6.1 glue_1.6.2
#> [9] yaml_2.3.7 rmarkdown_2.21 knitr_1.42 reprex_2.0.2
#> [13] xfun_0.38 digest_0.6.31 lifecycle_1.0.3 rlang_1.1.0
#> [17] evaluate_0.20
Referencing a prior Posit Community report: 105003