March 2026 monthly summary focusing on key accomplishments and business value. In pytorch/pytorch, delivered a feature that enhances transformer attention efficiency and flexibility by enabling Flexible GQA-style QKV projections within the concat-linear fusion optimization. This work relaxes shape constraints on weight matrices, allowing Q, K, and V projections to have different output dimensions, and uses split-based fusion to accommodate unequal sizes. The feature reduces fusion barriers for GQA-style attention, enabling more efficient GEMM fusion and broader architectural flexibility for model designers. Validated via the included reproducer script and related tests; PR 178523 merged and approved (with reference to the reproducer and reproduction results).